As explained above:
If you have bought the REs from the secondary market. You will not be able to apply for rights shares from the RTA’s portal. You will have to make an application either through Netbanking ASBA service provided by your bank, you can check out the process here.
In case your bank isn’t offering the option for application, you will have to make a plain paper application. You can download the application form here. The process for submitting the form has been explained on the form itself.