Hello Aspirant,

You can follow this link to find previous year's question papers for Mizoram Civil Services Examination, for all subjects:

https://mpsc.mizoram.gov.in/page/Old%20Question%20Paper-17-08-21-17-08-22

Some useful channels on YouTube are:

1. Kamliana
2. Unacademy UPSC
3. Study Point-Subodh

Hope this was helpful to you. You may ask if you have any other queries.

All the best for your preparations!!