You can look at your cook history by tapping the 3 dots in the upper right corner of the MEATER app Dashboard, then selecting "Previous Cooks".
From here, you can choose any cook to view the graph and temperature data, as well as any notes you left during the cook. You can also slide any cook to the left to mark it as a favorite (which will pin it to the top of the menu) or delete it.
If you ever need to delete and reinstall the app, or if you get a new phone, don't worry! As long as you're signed into a MEATER Cloud account, your cook history will be synced with any devices logged into that same account.