Once you created and verified your Membershyp account, you will have the default payout rate of 70%. 

If you have a Twitter account that is older than 4 months and has at least 400 followers, you can connect it to your Membershyp account within a few clicks. After that, your payout rate will be increased to 90%.

You can do that in your account at "Settings-->Promo (90%revenue share)"