If your gym is paying for your members subscriptions your members should not be asked for payment options. However, if you come across a scenario where you have sent your member the invite email and the member code,and they are still asked to input their payment info, it could be 1 of 2 reasons.
1 - Are you still paying for your members subscription?
Make sure you are still on the correct payment plan. In some cases a gym's payment may not have gone through and the membership plan will have changed to a members pay subscription. Go to your gym's subscription and update any payment details that may be incorrect or expired.
You can do this by going to your Admin Console >> Settings >> Subscription.
2 - Has your gym hit the limit for your current gym plan?
Once your gym plan has hit its limit any member attempting to join will be asked to pay for their own subscription.
You can check your member count by going to the Admin Console >> Settings >> Subscription.
If you have hit your limit, select "manage members" and sort the list by "Last Workout Result". You will be able to remove any members not using their subscription. If all your members are active on their accounts, you may need to go back to the subscription page and upgrade.