SQLite is not like a traditional DBMS in that it does not serve the content of the database to a computer network. It is actually kinda like just storing everything in a file. SQLite is will then allow your application to load that file and query it.
As such there is no need or advantage to a user account system as only programs on the same computer can interact with it anyway. The OS's file permission system should provide protection against not authorized reading/writing. Of course the machine on which this system is located needs to be secured as anyone with appropriate access on this machine can read/edit the database.
If you for example want to be able to only read table A but read and write table B then you should use 2 database files, one with only read permissions and the other with read/write permissions. How you do this is OS dependent.