I am trying to get the input from textinput

I have patch function added onSelect property of my button name "Add"
But whenever i try to use below formula, I get following error:
Patch('Global Numbers', Defaults('Global Numbers'),{Sourcing_Category:Add_Source.SelectedText.Sourcing_Category_Name}
"The type of this argument ‘cr63b_sourcecategoryname does not match the expected type ‘OptionValueValue’. Found type ‘Text'"
I am trying to fix this error since 3 days, no success yet 😞