Refer to this article if your version is above 7.4.1

Each department within an organization would have requirements to allocate specific Roles to their team members to function within the OrangeHRM system. As an example, the HR department could consist of Regional HR Admin, Recruitment Manager, Asset Manager, Global Salary Admin Etc..,
To accommodate such requirements, it is possible to Assign User Roles to individuals, during the process of creating the Role.
The following illustrations provide steps on how to create a User Role or search a User to assign a specific User Role.

Create User Roles

Filter the user list to find the user

Go to  Admin -> Users from the Main Menu. 

Step 1 - Click the Edit button. Then the Edit User screen appears as follows.

Step 2 – Change the relevant user role to the one you created. Click "Save". Then the Modify Region screen appears as follows.

Step 3 – By default ‘All Regions’ are selected. If you want to restrict to a Region, de-select ‘All Regions’ then click on the "Select Region" text box below and select region.

Step 4 – A list of regions is shown. The user can select a single region or multiple.

Step 5 – Click ‘Save’.