The most recent version of this documentation can be found at https://docs.dyalog.com/20.0/.
Monadic ⎕FMT means
⎕FMT 2 4⍴⍳8 1 2 3 4 5 6 7 8
Dyadic ⎕FMT means
'I3,F5.2' ⎕FMT 2 4⍴⍳8 1 2.00 3 4.00 5 6.00 7 8.00
The most recent version of this documentation can be found at https://docs.dyalog.com/20.0/.
⎕FMT 2 4⍴⍳8 1 2 3 4 5 6 7 8
'I3,F5.2' ⎕FMT 2 4⍴⍳8 1 2.00 3 4.00 5 6.00 7 8.00