You may have encountered a Mikrotik error when trying to create preshared key

Couldn't change wireguard peer<> - invalid preshared key (6)

This is because a Wireguard preshared key needs to be 256bit (32 byte) base64 encoded key. We have a couple different ways we can generate the correct format.

\1. Use Openssl to generate a random 32 byte password

openssl rand 32 | base64

\2. Create a 31 character password and base64 encode it

echo Thisisthepassword31characterslo | base64
VGhpc2lzdGhlcGFzc3dvcmQzMWNoYXJhY3RlcnNsbwo=

Now we can take this and add it to our config. The config option is

PresharedKey = VGhpc2lzdGhlcGFzc3dvcmQzMWNoYXJhY3RlcnNsbwo=

https://www.wireguard.com/papers/wireguard.pdf

https://forum.mikrotik.com/viewtopic.php?t=184469