I was dealing with a similar problem in my company not long ago. Solving it came down to reducing how much paperwork was needed and helping the team take care of what was left faster.
The first step is the easiest. Just go over exactly what your team is doing and why. Chances are that if your sales process hasn’t been optimized in a while, your team is wasting at least some time collecting information that isn’t necessary. Or that could be requested later, via email, so that the sales representative doesn’t have to be stuck on the phone collecting and writing down that info.
The second step is helping your team handle things faster, and that’s a little trickier. You may be able to speed things up by using forms, templates, and industry-specific tools like the door manufacturing software found on this link. But it can be difficult to solve this problem with broad strokes — you may need to go over the performance of individual team members to see who’s lagging behind and why.