The Light Phone II has a total device storage of 8gb to be shared by the operating system, phone history and various tools.
To view your device storage and settings for managing storage, go to:
Settings > Account & Info > Storage
NOTE: Must be on LightOS v312 or later to view device storage options.
Clearing Phone History or MMS History
Clicking "Clear Phone History" will automatically clear the device's entire history of conversations and call logs. The phone will retain all of its tools and stored contacts. "Clear MMS History" removes just stored images/videos that you have been sent, which often take up more space than the call/text history. Your conversations will still remain, but you cannot forward previous MMS messages manually as they will be removed.
Keep History Settings
By default, the phone will keep your history forever. You can also choose to have the phone automatically clear history that is older than 30 days. If you select to keep history for 30 days, all history that is older than 30 days will be erased.
NOTE: Clearing history is a permanent action and cannot be undone.