Go in your Garmin GPS to Menu > Where to? > Coordinates > Format

If you select the BOTTOM format (most easy): h ddd.ddddd° 
please enter these 2 fields:
North 10.00425° 
West 84.27207° 
In the GPS it shows as:  N 10.00425°   W 84.27207°


If you select the MIDDLE format: h ddd° mm.mmm' 
please enter these 4 fields:
North 10° 00.253' 
West 84° 16.325' 
In the GPS it shows as:  N 10° 00.253'   W 84° 16.325'


If you select the TOP format: h ddd° mm' ss.s" 
please enter these 6 fields:
North 10° 00' 15.3" 
West 84° 16' 19.7" 
In the GPS it shows as:  N 10° 00' 15.3"   W 84° 16' 19.7"