Deleting Messages does not free up storage
Look for the Messages containing attachments. Delete entire message discussions.
Why are messages taking up so much storage? It is possible that there are a lot of pictures or file attachments in the messages or there are a lot of spam text messages that automatically sync to iCloud.
What's likely stealing all the storage space are all the attachments you send and receive — audio, photos, stickers, videos, GIFs, and files.
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.
The second storage-saving strategy is to automatically delete old messages. Many people simply let the conversations accumulate for months and years without deleting any messages. This is very common. And with messages kept forever, the storage requirements for those messages will grow over time.
If your Android phone is running out of storage, you can clean it up by clearing caches, cookies, and unused files. Some of the most common culprits are photos, videos, and files that you deleted, but which still show up on your phone or tablet.
In general, Android SMS are stored in a database in the data folder located in the internal memory of the Android phone. However, the location of the database might vary from phone to phone.
Clear cache in Safari
Open Settings > General. Tap iPhone Storage and select Safari from the list of apps. Tap Website Data to view a breakdown of your data by website. Tap Remove All Website Data at the bottom of the screen, and confirm with Remove Now.
Disabling and deleting Messages in iCloud will remove all your conversations from your iCloud account. As a result, your text conversations will no longer sync across your devices.
When you set up iCloud for Messages, your messages are stored in the cloud instead of locally on your device. You can see them on any device that's set up for iCloud and Messages, including your iPhone, iPad, iPod touch, and Mac.
And don't forget your text messages–All those shared photos, videos, and GIFs can take up space. iPhone users can clear out big text attachments on the iPhone Storage screen. Another tip: Change your settings to save your text messages for a year or 30 days instead of forever.
You can choose to automatically delete your iMessages from your device after 30 days or a year, or to keep them on your device forever. For your convenience, iMessages are backed up in iCloud and encrypted if you have enabled either iCloud Backup or Messages in iCloud.
Your iPhone memory is full and you can no longer save new apps, photos, and other data on your iPhone. It also means iOS can no longer delete cache data and other system files to clear up storage on your iPhone.
Restart Your iPhone. Try restarting your iPhone if you have checked the iPhone memory and there is actually valuable space, but you keep seeing the message "Storage almost full". Press the power button for a few seconds, tap the slider to turn off the iPhone, and press the button again to turn on the iPhone.
Any messages currently stored in iCloud are now accessible on your device, and any new messages you receive on your device will be stored in iCloud.
Apple offers users the option to keep text messages for the past 30 days, the past year, or permanently. You can go to Settings > Messages > Keep Messages to have a check. If the message you need is within that time frame, then you should be able to access it on your iPhone.
When someone shares photos and videos with you using the Messages app, you can easily find them in the Shared with You section in the Photos app . (Automatic Sharing and Photos must be turned on in Settings > Messages > Shared with You, and your friend must be in your contacts.)