After logging in to Socrative through the Socrative Website, click on your initial in the top right corner and click Profile. 

In the header, select 'Account', and from there 'Manage Plan'. You'll then be able to manage your subscription on your account.

If you have a legacy Pro plan, you may have a license key with the option to toggle off and on/auto renew. If auto renew is toggled on, payment will renew automatically

by default. Subscription plans will renew automatically in 1 year or 1 month depending on plan subscribed. Please be aware, you will receive renewal reminders 7 day(s) prior to your renewal date.

If you used a coupon code, your plan will automatically renew at the original price on your renewal date. It will not be the same price if you had used a coupon code.

Once you purchase, your receipt will be emailed to the email address you use to login to Socrative.