If you have a registered agent, most will offer those services. You can look on the DE website directly to fill out and submit the forms (it's very straightforward), but even still I'd recommend running any documents by your lawyers and accountants to ensure accuracy.
If you are a Delaware C Corp, you can do it yourself (https://corp.delaware.gov/paytaxes/) but there is a trick. First, you will see a very big number of tax, do not worry, resubmit again, and your tax will go down significantly. If you are pre-revenue, it should not be more than $1,000.