In order to start receiving payments for the services you have provided on Instantgo, you will need to access the "Get Paid" section in your settings in the mobile application.
Per default, Instantgo recommends you to use PayPal.me and you can simply add your PayPal,me account to your profile so it can be shared more easily. Simply make sure to have an account (create one here). Feel free to use any other payment methods when dealing with another user. It is up to you and the other user to agree on a price and a payment method as payments will be made directly from the users to your own account (for example your PayPal account).
Requesting a payment from another user is very simple. Whenever you are in a chat conversation with a particular user, simply click on the $ you see at the top right of your screen. In that screen, you will be able to decide how much you want to get paid for a specific transaction and send a payment request instantly. You will also be able to accept the payment in order to let other users reach you over the phone and more (you can enable or disable those options for each individual user at anytime).