Google services like Gmail and Drive are used by millions of people every day, but the 15GB of free storage fills up quickly. If you are also getting the notification of storage full again and again, then it can be easily reduced. Many users find that saved files in their Drive are the only ones using up the storage, while attachments in Gmail also take up a lot of space.
Old emails in your Gmail over the years include attachments like photos, PDFs, and presentations. Their presence in the account wastes storage. From small to large attachments all form a part of the 15GB of free storage, which eventually fills up the storage.
Change Gmail Settings
Delete emails with large attachments