Partnership tax return

Hi, I am preparing to submit a tax return for a partnership, and I understand that I need to file: • SA100 and SA104S for myself • SA800 for the partnership I have a few questions: 1. If I submit the SA800 by post, can I still file the SA100 online, or do I need to file it by post as well? 2. If I file my self-assessment tax return online, does it automatically include both the SA100 and SA104S? Thank you very much!

Hi CHI HO CHIU,
1. Yes, SA100 can be submitted online> 
2.You need to tailor the your tax return at section 3 to suit your types of income. 
Please see further help here: 
How do I tailor my Self Assessment tax return?
Thank you. 

Hi,
Please see the following link:
Who must send a tax return
Thank you