when i goes to set ringtone from my phone it shows one drive...samsung j7 max phone

Well the phone only has one 'drive' so to speak. Then it also has a slot for a SD card, which you would have to have gotten and inserted into the phone.

However, often, phones will only search the phone itself for any ringtones. So you need to save the file(s) you want into the phone's ringtones folder.