can i create an online form where managers enter their numbers and it populate a dataset in domo
Where are you thinking of hosting this? There is a google sheets connector that may be useful or if you wanted to have them enter it in domo there is a domo form card option.
There are several ways you can accomplish this, however there aren't any native Domo methods that would help on this. Domo is a great tool, but accepting user input isn't necessarily one of those use-cases at this time.
As far as what Domo supports, the most straight-forward approach could be a shared Excel sheet which your managers have access to and gets pulled into Domo. This can then be joined with other datasets as needed.
A clunky method is to let your managers create a Domo Webform (shared or personalzied to themselves) which they would update whenever they need it.
If you're familar with software development, you can get far more creative with this though and creative a custom web form, which saves to a database, etc.
I agree with @dthierjung
The best option within Domo would probably be the Domo Webform. However, if you are using a third party product, there can be some better options to accept user input and push that through to Domo. We are using Sharepoint and SmartSheets and both options have connectors available to bring the data back into Domo.