First of all, you should back up your important files, such as address book, phone records, SMS records, photos, etc ... These files should be backed up to the cloud disk or computer as much as possible so that we can resume using them in the future.

Second, see if you have any chat records of important software to save. If yes, export; If not, skip directly.

Third, it is to restore the factory settings, clear all data, and completely restore the mobile phone to the default state of the system. So that the junk files in the mobile phone won't leave anything.

Fourth, just download some software you need. After downloading the number, restore the chat record or something (if it's not important, don't restore it. That will only take up space)

Fifth, restore the backup file from the cloud disk or computer. In this way, the important data of your mobile phone will not be lost. But also can remove the troubles caused by junk files to the maximum extent.