How to use a calculator to evaluate tan 3 ?

Degrees are more known to me than radians. Hence, continuing with degrees first.
${\displaystyle \tan 3°=0.0524077793}$
You only need to tap on "tan" and then enter the angle in degrees or radians, as supported by your calculator.
If you write this into Google Assistant or command it, it will typically take it in radians form (assuming you haven't changed any settings). You can then select one of the three available units of angle.