1111111111111111111114oLvT2

[NotATether]

Can you explain how to do this?

Depends on your wallet software. With Bitcoin Core, then createrawtransaction has a data field you can specify which will create an OP_RETURN output. In Electrum, you can simply write OP_RETURN followed by the hex encoding of whatever data you want in the address field.

Sorry to raise this question again, but I see that Bitcoin Developer lists this as a required field in the second parameter (which is also required). If I do not want to make an OP_RETURN output, should I just pass a {"data": ""} argument? Or will I get away with leaving the object out, as I've seen Bitcoin Developer examples over here do?

[o_e_l_e_o]

Sorry to raise this question again, but I see that Bitcoin Developer lists this as a required field in the second parameter (which is also required). If I do not want to make an OP_RETURN output, should I just pass a {"data": ""} argument? Or will I get away with leaving the object out, as I've seen Bitcoin Developer examples over here do?

Just leave it out. It is "required" only if you want to create a data output. If you don't want a data output, it isn't required and can be left out entirely.