Go to > Sound & vibration > Phone ringtone and select it from the list. For iPhone:

To assign it specifically to your grandmother, open her contact in the app, tap Edit , and select the custom Ringtone or Text Tone .

Use a file manager to move the file to the folder (or Notifications folder for text alerts).

: Search for "Бабуля звонит" or "Babushka zvonit" on the Zedge website or mobile app. It is the most common source for custom Russian-language voice ringtones.