How to Send Crash Log to Discord - ImpactDevelopment/ImpactIssues GitHub Wiki
Upload latest.log from the launcher's logs folder. If you need more help than that, read the instructions for your OS.
Some people may ask you to upload the logs to a "pasting tool" such as Pastebin. In that case, just open latest.log and paste it into the service, then copy the public link to it.
Hold the Windows key and press R. Type %APPDATA%\.minecraft\logs in the Run box, and drag latest.log into the Discord window.
Hold the Command key and press space. Type ~/Library/Application Support/minecraft/logs into Spotlight, and drag latest.log into the Discord window.
Upload latest.log from ~/.minecraft/logs. If you installed the launcher using Flatpak, which is unlikely, you're looking for ~/.var/app/com.mojang.Minecraft/data/minecraft/logs. But you already knew that if you installed Impact there.