Change ICloud username

I assume you are talking about the Apple ID - the email address you use to log into iCloud and possibly elsewhere as well.

If your primary address (the ID) is an @icloud.com, @me.com or @mac.com address you cannot change it. If it is a non-Apple address you can change it as follows:

Firstly, sign out of iCloud on all your devices: go to each of your devices and sign out in System Preferences (or Settings)>iCloud - 'Sign out' on a Mac, 'Delete this account' on an iOS device (this will not delete the account from the server). If you have 'Find My iPhone' etc enabled you will need to disable it first. Your synced data will disappear from your devices but will reappear when you sign back in.

Create a new email address, for example at Yahoo or Gmail, or anywhere convenient (or you can use an existing address as long as it is not associated with an Apple ID). You can change it to another Apple address only if it's listed when you click the link to change (in practice this means your main @icloud.com address, and the equivalent @me.com and @mac.com versions if you have them: it does not include email aliases).

Go to http://appleid.apple.com and click 'Manage your Apple ID'. Sign in with the current ID.

Where it says 'Apple ID' and gives your current ID email address, click 'Change your Apple ID'.

Enter your new address and click 'Save changes'

Sign back into iCloud on all your devices with the new ID and password. Your synced data will reappear (give it time).

I reiterate - before you start, sign out of iCloud on all your devices. Failure to do this will lead you into difficulties.

Welcome to the Apple Community.

If you create and use a wholly new (not amended) Apple ID, you won’t be able to transfer anything you have purchased from the iTunes & App stores to the new ID, but you can transfer your iCloud data (calendars etc) with a little patience.

iTunes & App Store. 

You may want to think about continuing to use the previous Apple ID for the iTunes & App stores (as well as iBooks) so that you can continue to use your purchased content without a problem and just use the new Apple ID for iCloud, Messages and FaceTime. 

If you do use your new Apple ID for the iTunes and App stores, you will be able to authorise and play previously purchased content from the iTunes Store on a computer, but may encounter difficulties using this content on an iOS device.

Whilst you won't lose apps you purchased using the previous Apple ID immediately, you will no longer be able to update them. 

If the previous Apple ID is going to continue to be used by a family member who is part of a family sharing set up which will include your new Apple ID, you will be able to share the previous purchases as well as any further purchases they make under that Apple ID. Be aware though that when using Family sharing, unless each family member has their own credit sum from iTunes gift vouchers, the organiser of the family share set up will pay for any purchases made by any family member.

iCloud. 

Moving your iCloud data from one Apple ID to another is achieved more easily on a computer than it is on an iOS device, indeed certain aspects of the move can only be done on a computer. However, whichever device you choose to move your data on, you should do so by turning individual iCloud services off one at a time and not sign out of the account until all services have been turned off and dealt with. (Settings ➔ Apple ID(Top) ➔ iCloud on a mobile device and System Preferences ➔ iCloud on a Mac)

If you have purchased extra space for iCloud under your previous Apple ID, this won’t be transferred when you change the Apple ID you use and you will need to re-purchase the required space under the new Apple ID.

iCloud Drive. Save data from your iCloud Drive to a computer before turning off this service. You can use the Finder on a Mac or through iCloud.com if you use a PC. Simply move the data to your new Apple ID once it is set up.

Photos. Make sure you download and keep originals when prompted when you turn iCloud photo library off, you want the photos to remain on your device and merge with your new library when you set up your new Apple ID.

If you use photo stream be aware that there may be more photos on your device than there are in the cloud, photo stream in the cloud only keeps up to photos for 30 days, if you have older photos on your device you may want to copy them to a computer before turning photo stream off.

If you have created any shared albums you will need to create them again once you have set up your new ID, any photos that anyone else has added to your shared albums should be imported to your camera roll/library before you turn off shared albums.

Mail. Once you change your Apple ID, you will have a new iCloud email address. So that you don’t miss any email which is sent to your old address, you can arrange to have it forwarded to your new address (or any other address), you can set this up at iCloud.com ➔ Mail ➔ Preferences ➔ General.

Contacts. You will be given the opportunity to save contacts to your device when you disable this service, merge them when prompted when you re-enable the service after signing into your new Apple ID.

Calendars. You will be given the opportunity to save calendars to your device when you disable this service, merge them when prompted when you re-enable the service after signing into your new Apple ID.

Reminders. You will be given the opportunity to save reminders to your device when you disable this service, merge them when prompted when you re-enable the service after signing into your new Apple ID.

Safari. You will be given the opportunity to save Safari Data to your device when you disable this service, merge them when prompted when you re-enable the service after signing into your new Apple ID.

Notes. You cannot save notes easily. On a Mac you can drag them into a different account and then drag them back once you have set up your new ID, but on an iOS device you will essentially need to copy and paste them into new notes when you have set up the new Apple ID, but you will need to share them before you turn of notes for the old Apple ID, either by messages, email or similar.

Back up. You can’t save your existing back up you will have to start a new one once you have set up your new Apple ID.

Keychain. You will be given the opportunity to save passwords and credit cards to your device when you disable this service, merge them when prompted when you re-enable the service after signing into your new Apple ID.

Your 'user ID' (login) for iCloud is an Apple ID. If you have another Apple ID - perhaps for iTunes and here - then you can't make the two the same: you can change either of them using the method I described above but you can't change to an email address which is or has been associated with another Apple ID: and you can't have two separate IDs using the same login address.

If you do indeed have two separate accounts the only thing you can do is to sign out of iCloud and sign into it with the other Apple ID, but you would have to save everything currently on iCloud to your computer first and then resync it to the new iCloud account.

Frankly, none of this is likely to be worth the effort.

Use a web browser and sign in appleid.apple.com with your Apple ID and password , fill up the security answers for questions ( if it's a secondary authentication account ) .

In Account section click on edit , you can see the first name , middle name , last name .

Take cursor in the dead end of the field of first name , and click on delete button on the key board , and type you new first name , apply the same procedure for middle name and last name and you should click on " done " to save the data

What do you mean by username. Do you mean your Apple ID name?

yes

want to make my user id for icloud the same as my user id for apple ID