How can I track customer expiry dates

Hi there, I am new to IS so hoping someone can lend some expertise here !

I have a subscription based business and am trying to find an easy way to keep an eye on which subscriptions are coming up for renewal so I can reach out to my customers - ideally I would have a view of this on my dashboard.

My product is delivered via an online course platform called thinkific and i manage all billing etc through freeagent.

Is there an easy way for me to input an expiry date against a customer in IS and have it show on my dashboard if for e.g. it is due up in the next quarter?

Thanks so much!

Under Ecommerce->Reports there are a number of reports that should help: