Will my independent research work without formal appointment letters be accepted as valid work experience for visa or university applications?

It depends. Independent research work can be accepted as valid experience for university or visa applications, even without formal appointment letters, if you can clearly document your involvement.

To strengthen your application, provide:
- Detailed project descriptions outlining your role, objectives, and outcomes.
- Reference letters from mentors or collaborators who can verify your work.
- Evidence of publications or presentations related to your research.
- Proof of funding or grants (if applicable).

Universities and visa authorities typically prefer formal documentation but may consider alternative evidence if it is thorough and credible. Present your research experience clearly and with supporting proof for best results.