When I played bf4 solo mode I noticed that there are binoculars that target enemies. How can I get this in multiplayer mode?
You can't. To target enemies you have to aim at them and press the Q key. It will show a red triangle above them.
If an enemy is in the vehicle, it will show a small red pic of that vehicle. Like that you and your teammates will see where the enemies are.
Just don't forget, that it lasts only a few seconds and not constantly like in campaign
They are not available in multiplayer. The closest thing you could get is the PLD for Recon, which allows you to laser paint vehicles.
Edited for clarity, thanks Dupree3
It's also worth noting that it uses infrared vision, making spotting easier.