Maximum free storage of Google drive/account is 15GB.
However, you can buy more storage like 100 GB by paying a monthly or annual fee to Google.
Let us know if you need any further help regarding this matter.
Will be happy to help.
Every google account starts with 15GB of free storage that's shared across google drive,photos and so on.
If u want to upgrade it, u can pay money and upgrad it by 100GB.