How do I get into my old iphone 7 when I forgot the passcode?

See these instructions, keeping in mind that if you don't have a backup all data will be lost on that device (except those that you eventually synced to iCloud):

If your device is running iOS 15.2/iPadOS 15.2 or later, AND if you have created a backup to iCloud, you don't need a computer:--> How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

Shouldn't be this case (iOS/iPadOS earlier than 15.2), you need a computer. If you don't have a computer, borrow one from your friends/relatives/neighbors or ask for help at an Apple Store or Authorized Service Provider, then read these suggestions.

Given that to remove the existing passcode you must connect your device via USB to a computer (a Windows PC running the latest iTunes version, or a Mac, which can run iTunes or Finder, depending on the macOS installed on it), pay attention to the specific gestures that you need to perform while connecting your device to the computer.

These are the instructions to re-gain access to your iPhone/iPad:

If it is an iPhone:--> If you forgot your iPhone passcode - Apple Support

If it is an iPad:--> If you forgot your iPad passcode - Apple Support

Also, take a look at this support video about the same matter (for both iPhone and iPad):

https://www.youtube.com/watch?v=7s8-zLG9ySQ

Regards

Giulio

Hello,

I see you have forgotten your iPhone 7 (with iOS 14) passcode.

You can use a computer to reset your device, as described in this article --> If you forgot your iPhone passcode - Apple Support . Read the support article for full information. You can also watch the 5 min. 16 sec. video "How to restore your iPhone if you forgot your passcode" at https://www.youtube.com/watch/7s8-zLG9ySQ

This will result in erasing the iPhone. You can, however, restore it from a backup as described in this support article --> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Here are resources if you are prompted for your username and password and have forgotten them:

If you forgot your Apple ID email address or phone number - Apple Support Note that typically this is an email address you use.

If you forgot your Apple ID password - Apple Support

If you do not have a computer, use this link Find Locations to find an Apple service location, or ask a friend if you can use theirs. This could be either a Mac, or a PC with iTunes.