Enterprise users can enable or disable automatic agent updates in 0patch Central for each group separately (or for subgroups using inheritance) under the group's SETTINGS. There, set the "Update agents automatically" setting to "Enabled", "Disabled" or "Inherit from parent group". To do this for all computers, set this setting for the root "All Computers" group.
Non-Enterprise users can enable auto-update directly on the computer with 0patch Agent installed. To do so, change the registry value "AutoUpdate" under HKEY_LOCAL_MACHINE\SOFTWARE\0patch to 1, and all subsequent updates will happen automatically without your intervention. (Note: this registry value is ignored by agents in Enterprise accounts.)