As explained the the article "How to add drivers" you can add new drivers through a company panel and create their profile manually.
You can also allow your drivers to register through their apps. For that open your company panel, choose tab "Company", find "Driver options" and tick "Allow driver signup via driver app".
Now your drivers will be able to send their requests for activation through their driver app.
Once the driver downloads the driver app he will have to sign in and fill in all the requested info to be sent to the company he wants to join. Having submitted the request for activation he will see the following :
Now that the driver's request has been submitted the request has to be accepted and processed following the next steps:
a. Go to the tab "Drivers" in your company panel and select the sub tab "Waiting for activation (1)"
b. After that, press on the driver waiting for activation information and choose the "Edit profile" option at the bottom left corner of the screen.
c. On entering the profile you should add the driver's vehicle class from the drop down list "Vehicle class" and press the green button "Save" at the bottom right corner of the screen .
d. Having saved the changes you should re-enter the "Edit profile" screen as per the steps from point "b." and press the green button "Activate".
e. At this stage the driver's status will change to "Invited "
f. Now the driver's "Activation request" has been processed, so, the driver can enter his app and start his first shift. Once he has done that, his status in your company panel will change from "Invited" to "Active".
All done! Your driver's request for activation has been successfully processed and you have a new member of your fleet now.