How can i measure Gain in multisim 14
You can measure gain with the following steps;

1- Click Simulate > Instruments > Measurement Probe

2- Place the probe on the wire between the voltage source and the resistor.

3- Click Simulate > Instruments > Preset Measurement Probes > Voltage with reference to probe

4- Select Probe1 as the reference

5- Place the probe on the output. Notice that the visible measurements includes gain.