Follow these steps:
1. Insert a Dropdown1 and on its Items property put: The name of your table that contains the dropdown list.
2. In the Default property of the TextBox (Example Textbox1) which will hold the selected item from thr dropdown put: Dropdown1.Selected.Value
3. To send the data in the Textbox1 to the datasource, Project Information, Put the formula OnSelect of the Button:
Patch( 'Project Information', Defaults('Project Information'),
{'Project Location': Textbox1.Text } )
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