I’m trying to wire a 110 receptacle to my electrical panel outside and I see no neutral terminal bar. I know the black goes to the breaker for power and the ground goes to the ground terminal but this box has a terminal on each side and both of them have grounds hooked into them. Where do I put my white neutral??
Edit: Here’s a picture of the inside:
Since you are working in your main panel, where your service disconnect lives (in fact, I can tell offhand from the construction shown in your photo that this is a meter main device we are looking at, so it can't be anything else besides your main panel), you can land the white neutral wire on either the left-hand or the right-hand neutral bar. This is because the neutral and ground are bonded together here (and only here!), so the busbars down the sides do "double duty" as neutral and grounding bars as a result.
However, that's not the only thing you need to do. That Square-D HOM115 you put in for the new circuit has no business whatsoever being in a Siemens meter-main, so you'll need to remove it and return it, then install a Siemens Q115 in its place. Once that's done, you can wire up the circuit as described already, with white and bare to separate holes on the neutral (grounded) bars, and black to the breaker lug.
Last but not least, you will want to use an inch-pound torque screwdriver to tighten the busbar and breaker connection setscrews to their labeled tightening torques. This is required by 2017 NEC 110.14(D), and is a good idea anyway, since the performance of set-screw type connections depends rather critically on proper torquing. You don't want your new outlet to give you the loose lugnut now, do you?
It sounds like this is your main panel.
A main panel is the only place that neutral and ground are connected at the same point. Make sure the neutral is the only wire under a screw; if there is limited holes available, it is OK to have multiple ground wires in one hole if the panel is listed/labeled for it. I have seen up to 3 ea listed but most are listed for 2 grounds under 1 screw.
If the circuit is for outside make sure to have GFCI protection.
