Regarding / in regrads to

[sh.hazeri]

which one is more accurate :

... I just wanted to provide you more details in regards to the case#123 ....
... I just wanted to provide you more details regrading the case # 123 ....

[bhaisahab]

which one is more accurate :

... I just wanted to provide you more details in regards to the case#123 ....
... I just wanted to provide you more details regarding the case # 123 ....

The second one is correct, but you probably don't need the article before "case".

[bertietheblue]

'in regard to' (without an 's') is not wrong but it's very formal and wordy. That said, I see it all the time in the legal documents I proofread, as I do 'with regard to', 'in respect of' and 'with respect to'. They all essentially mean the same thing as the more common 'about'/'concerning'/'regarding'/'relating to'/'on'.