Does Stripe have an element that would capture a customers card details but not process any payment?
In my case, I have a form that a client fills out but payment is not processed at that time as the final charges will always change based on what the client needs are. Payment would be processed at a later date.
I did see that WordPress / gravity forms have a module that does this but I would rather not have to create a WordPress site.
You can use Stripe.js with Elements (https://stripe.com/docs/stripe-js) or Stripe Checkout (https://stripe.com/docs/checkout) to collect your customer's card details securely.
Both Stripe.js and Checkout allow you to tokenize a user's credit card details. You can then use those that token/source on your backend to create a new Customer with that token [0] or update an existing Customer.
The Stripe recipe's page actually has an example of using Stripe Checkout to update a user's card details (https://stripe.com/docs/recipes/updating-customer-cards#using-the-token-to-update-the-customers-card).
[0] https://stripe.com/docs/api/customers/create?lang=node#create_customer-source
Hope that helps!
UPDATE: adding that the new version of Stripe Checkout is a hosted page that allows collecting card details for future use via its Setup Mode: https://stripe.com/docs/payments/checkout/setup#retrieve-setupintent
