Hi mariia41,
Thanks for posting in Apple Support Communities.
Apple ID is meant for single user use. It would be better for you to create your own Apple ID. You each will have access to each other's information while you hare the same Apple ID.
First, back up your iPhone to iCloud or your computer, and then sign out of the current Apple ID. All apps will be linked to the old Apple ID so you will need to remove them and download them again once you are signed in with the new Apple ID.
Create your new Apple ID and sign in on your iPhone.
How to create a new Apple ID - Apple Support
Sign in with your Apple ID - Apple Support
Regards.