In Essential Forms if you click Configure>Firm Data, then click on the Law Firm subtab.
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Click the check box, "Use firm data when adding new clients/matters to the database" that should make the fields in that Law firm tab active.
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If that is done immediately all new clients/matters/forms will then have the new firm address for all users on that shared Essential Forms database.
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On previously saved clients/matters/forms where the old address needs to be changed to the new address, the user will have to click on the Matter folder under the Client, in the General tab, under Firm click the three dots "..." and click "Select" to pick the new address from the stored list of law firms:

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Then, all the previously saved forms under that Matter (requiring the new firm address) will need to be opened and then click Edit>Refresh all open form with current client info on the Opened Forms tab:
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