Hi, this is called the "probe" block from Simscape libraries (not to be mixed with Probe from Simulink libraries). You can use it to pick a variable from other blocks and outputting from this block at any desired locaiton in the simulink canvas. You need to be working with at least release R2020a.
we do have as well block called "multimeter" but is used with a different technology.
hope this helps
Vasco
