I have discord.js installed but the error still pops up

Error: Cannot find module 'discord.js'
Require stack:
- /home/runner/Ticket-Bot/index.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/home/runner/Ticket-Bot/index.js:1:20)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)