Your top conversations are your most frequently used message threads. If you have photos, videos, GIFs, memes, or other media saved from other conversations that are being stored in iCloud, this could be why Messages is using most of your iCloud data.
Deleting Messages does not free up storage
If you could delete the Messages app it would clear the lot but you cannot.
Delete old text messages
Don't worry, you can delete them. Be sure to delete messages with photos and videos first — they chew up the most space. Here's what to do if you're using an Android. Go to your Messages app and press down on a message or conversation until you see a checkmark and the word Delete.
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.
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.
Android clearing data should not delete your text messages.
This means that if you have a message stored in the “Messages” app and then delete it, it will still be saved on your device, even if you clear all other apps and folders.
If you're seeing an "Insufficient storage available" message on your Android, chances are that you've used up most of your device's available memory. To fix this, you'll need to make some space by deleting apps and/or media; you can also add external storage, such as a Micro SD card, to your phone.
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.
It's easier to keep secrets.
But automatically clearing your texting history every 30 days can help you avoid getting in trouble if your phone slips into the wrong hands.
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.
You can also access the font size setting by going to Settings > Accessibility > Font Size. Android Magnification feature: Go to Settings > Accessibility > Magnification. Tap the slider to turn it on.
Sometimes the "Android storage space running out but it's not" issue is caused by the overwhelming amount of data stored on your phone's internal memory. If you have many apps on your Android device and use them simultaneously, cache memory on your phone can be blocked, which leads to Android insufficient storage.
With Messages in iCloud, anything you delete from iPhone is also deleted from your other Apple devices where Messages in iCloud is turned on. Deleting messages changes only your own Messages conversations, not those of your recipients.
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.
Clear cache: Deletes temporary data. Some apps may be slow the next time you open them. Clear data storage: Permanently deletes all app data.
Go to Settings > General > [Device] Storage. You might see a list of recommendations for optimizing your device's storage, followed by a list of installed apps and the amount of storage each one uses. Tap an app's name for more information about its storage. Cached data and temporary data might not be counted as usage.
While it's not strictly necessary, deleting your iPhone's cookies from time to time can help you save space and fix some browsing issues. What are cookies? These are small files that keep track of what you do online.
Clearing your cache on Android can free up valuable space and resolve issues with your phone's battery, speed, and security. Old cached data can corrupt, causing larger performance problems. If a particular app receives an update, the cached data from a previous version can cause conflict.
Some phone companies also keep records of sent text messages. They sit on the company's server for anywhere from three days to three months, depending on the company's policy. Verizon holds texts for up to five days and Virgin Mobile keeps them for 90 days.