A family of Microsoft relational database management systems designed for ease of use.
As Tom said an Access database is a container containing several objects; forms, tables, reports etc. You cannot open an object without providing access to the database.
However, a multi-user Access database NEEDs to be split between a back end (the tables) and a front end (everything else). the back end is stored on a network share and the front end(s) given to each user. The front ends are linked to the tables in the back end.
And therein lies the solution to your problem. You can have multiple front ends, each linked to the same back end. These front ends can load JUST the form you want the users to use. The Nav Pane can be hidden and access to design elements restricted. All without using code. You then install those restricted front ends to the users who will do data entry.