Hi

Presuming you are using Drupal and the IForm module then you have to do three things,
1. Create a permission to access the form,
2. Create or choose a role and grant it that permission,
3. Assign users to that role who should have access.

You do that as follows,
1. Edit your form and under Other IForm Parameters enter a value for "Permission name for view access control". A typical value is "online recording"
2. If you need to add a role, do so in the normal Drupal way. Go to the permissions page and scroll down to the iform module section. Check the permission that you created in 1 for the desired role.
3. Give your chosen users the role that was allocated the permission in 2. You can check a number of users and give them the permission in one step without needing to edit each individual.

Jim Bacon