Not necessarily. This decision is left completely down to you when you’re publishing the request.
Check out the screenshot below:

If you choose to leave these two boxes blank, when your client receives their request, they’ll be provided with a link to register on the system and access it. If they are already registered, it will just send them a link to the request.
Now take a look at this:

If you choose to tick “Allow share via link without requiring login”, then your client will receive an alternate link instead, which will allow them to begin filling in information straight away without registering. However, it’s worth noting that anyone in possession of that link can access the request so, if this is a potential worry for you, we’ve got you covered.
You can also do the following in conjunction:

By ticking “Protect share with a pin code”, your client will receive a randomised pin code along with the link that they’ll be required to enter when attempting to access it.