My iphone update link plz

have you read thru this support article for updating?

Update your iPhone, iPad, or iPod touch - Apple Support

Note that your iPhone 6 cannot be updated beyond iOS 12.

need more storage for update?

If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support

issues?

Updating iOS: common issues and solutions - Apple Community

video..

iPhone 6 cannot be updated to anything higher than iOS 12.x, which you probably already have.