How do i delete the old gmail on my phone?

[Destinyy .]

I have a phone, that has my moms gmail in it, my mom said she never used gmail and that it was my sisters phone, i downloaded applications, a few weeks ago, i tried downloading instagram today on this phone but it needed the password of my moms gmail. How do i restart it? Do i get to download stuff again in the new gmail account? Please help me.

[GOOFY]

It depends on your operating system of your phone. Is it iOS or Android?

Either way, uninstall the GMAIL app is there is one. Also, try going into settings>email then removing your moms account.

I hope I helped.