How can I convert text to reference ? Ex: ISNUMBER(ADDRESS(6;10;2.
 

I'm trying to use above function to avoid doing it by coding. However ADDRESS
function returns text and I cannot convert it to a reference, in order to use
its result as input to other functions (like ISNUMBER or CELL).

If I understand you correctly, try

=INDIRECT(ADDRESS(G7,H7))

for example

HTH,
Bernd