Disclosure of HMRC login details - Mandatory Entry of 3rd Commercial Software??

Hi, It is the first time I will file self assessment tax return online for the 2022/2023 tax year. As I need to apply for split year treatment and SA109 should be completed and submitted together with SA100 tax return, I will use one of the 3rd commercial software listed in HMRC's website for filing my self assessment tax return to HMRC. But, I wonder if this software company is authorized to obtain my government gateway ID, its password, UTR no. and NI no. while I create my account in their system prior to submitting my tax return (with other supplementary pages) to HMRC. (PS: while creating my government gateway user ID, I was told to "never share your Government Gateway user ID or password with anyone else".) Please advise. Secondly, I would like to confirm with HMRC if the above entry elements are mandatory for the linkage between HMRC system and the tax system of the recognized software company to check for my personal tax account and submission of my tax return to HMRC. Thirdly, I would like to ask if the 3rd commercial software (not HMRC online) is used for submission of my tax return, am I able to receive any notification from HMRC to prove that HMRC has received my tax return via that 3rd party software. Your expert advice is sought for the above 3 concerns, please. Thank you.

Hi KuenHK,
The 3rd party software uses your login details to submit the tax return to HMRC.
If you don't supply this information you won't be able to complete the return using the software.
You will be able to see on the HMRC account when a return has been submitted.
Thank you.