Will not let me update

No. iCloud is a syncing service and has nothing to do with the physical memory on your iPhone. You're going to need to delete things you don't need, use or want on your iPhone. This can include apps, photos, messages, email, music, videos, files, etc.

I would like you to realize and know one important thing and that is that there is NOTHING that you can do to increase the physical storage capacity of your iPhone. Your iPhone's storage capacity will forever remain the same as the day you bought it. The only way to create free space physically on your iPhone is to delete Photos, Videos, music, App data etc.

You can purchase ➔ iCloud Storage from Apple where you can create and save your iPhone backups and synch (Not Store) your Messages, Photos, Contacts, Calendars, Notes and Reminders. Note that iCloud Storage is NOT an extension of storage capacity of your iPhone. Just wanted you to know some facts.

Having said that, you can choose to Optimize Storage on your iPhone for all the Photos. What this action will do is store your original quality photos on iCloud and a small size photo on your iPhone. This takes up less space on your iPhone while maintaining the actual size on iCloud. This will free up space on your iPhone while making good use of iCloud. If you would like to try this then open Settings ➔ Photos ➔ Optimize iPhone Storage : Ensure that this option is chosen and has a checkmark on it.

Axel F.

oliverio148 wrote:

if i buy icloud storage will it let me update with that storage?

No! Read and understand the article linked above.

Also:

If your iPhone, iPad or iPod touch won’t update - Apple Support