Your membership is run from the Ultimate Member Plugin which you access by clicking on the left hand menu.   Choose the Dashboard option to manage your memberships in the easiest way.

Where you have memberships to approve, they will appear in the Pending Review section. To manage these memberships, click on the ‘Pending Review’ lettering and you’ll see a list of those users that are waiting for action.

Select the User or Users that you wish to affect (you can deal with them in bulk if you have a lot to process) and then click on the drop down box ‘UM Action’.  You can then choose the action you wish to take and click on the Apply button to affect the users you have selected.