Don't Download Any Email at All If you want to get extreme or want to use your storage space for something else, don't set up any email accounts on your iPhone. That way, email will take up 0 MB of your storage. If you don't set up email accounts, that doesn't mean you won't be able to use email on your phone.
Free up space with Gmail. With the Google One Storage Management Tool, you can review and free up storage space by deleting emails in your trash, spam emails, or emails with large attachments.
Check the Sent folder or any other folder you think may contain emails you can delete. Regular emails do not take up a lot of space. To free up the most space in Gmail, you can delete emails that contain attachments, such as documents, photos, songs, etc.
Apps: Installed apps and their content, and content stored in "On My iPhone/iPad/iPod touch" directory in the Files app, and Safari downloads. Photos: Photos and videos stored in the Photos app. Media: Music, videos, podcasts, ringtones, artwork, and Voice Memos. Mail: Emails and their attachments.
Note: Mail stored in iCloud counts toward your iCloud storage. If you run out of iCloud storage space, you won't be able to receive new messages at your iCloud Mail address until you make more storage space available.
Emails can take up tons of space on your Android operating system. If you keep thousands — or even hundreds — of emails around, then it's time that you clear a significant amount of space by deleting these emails in Gmail.
Remove videos, books, and music stored on your phone
Sometimes what's taking up the most amount of storage are the data and documents stored within an app on your phone. You can find out if that's the case by once again heading to Settings > General > iPhone Storage and then clicking on an app.
Should you delete old emails? Yes, it will free space for new important messages, attachments, and files. Deleting old messages will also help keep your inbox clean and organized.
Delete old text messages
You'll be surprised to see how much storage space your text messages take on your smartphone. You may not even realize those messages are being saved to your phone. Don't worry, you can delete them. Be sure to delete messages with photos and videos first — they chew up the most space.
Deleting Emails Is Best For
When you need to clean up your free storage with Gmail – even though they offer 15GB (but that's across Gmail, Google Drive, and Google Photos). Deleting old and unread emails is a great way to claw some of this storage back.
Deleting removes emails from your inbox. It does save up space, but you won't be able to ever again access your emails.
A common reason for this issue revolves around the Recently Deleted album in the Photos app. This album allows you to recover deleted photos and videos for up to 30 days after deleting them.
Backups of your devices are often the culprits behind a full iCloud storage space. It's entirely possible you had your old iPhone set to upload backups to the cloud automatically, and then never removed those files.
Clearing your cache removes stored data that helps websites and apps open faster, while offloading temporarily uninstalls an app without deleting any of the documents and data associated with that app. Both methods can help speed up iPhones that are slowed down by low storage.
Gmail. If you run out of storage space, this may happen in Gmail: You can't send or receive messages. People who send messages to you may receive a notification that the message cannot be delivered.
Deleted messages get moved to a Deleted Items folder, where they are held for 30 days and then automatically purged.
iCloud backups don't include: Data that's already stored in iCloud, like Contacts, Calendars, Notes, iCloud Photos, iMessages, Voice Memos, text (SMS) and multimedia (MMS) messages, and Health data* Data stored in other cloud services, like Gmail and Exchange mail. Apple Mail data.
But the Mail app may sometimes use a large amount of space, which is particularly onerous on storage-limited 16GB iPhones. This is similar to the problem with the Mail app on a Mac. On both iOS and OS X, the Mail app may take up gigabytes of storage space because it wants to store a complete offline copy of your email.