SharePoint online list form

[aakif_aslam]

I'm trying to create list to raise tickets, main concern is to add multiple cascading drop-down list where they share a relationship (parent-child). As I'm working over SharePoint online thus can't use content editor/script editor web parts. If there is any other way to do this ?
Could be a real help.

[#2]

Hello @aakif_aslam 

I would recommend to the user PowerApps, please check the link below:

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/dependent-drop-down-lists

Alireza

[#3]

Thank you for your response.
I tried earlier creating those ddl with PowerApps.
After publishing it the problem I faced is that I can't save the form at all, even after all the fields are completely filled.

[#4]

@aakif_aslam  as a side note, Microsoft did, in fact, have an issue whereby if a custom form was not able to be saved because it was missing required data, then the form would not save.  A workaround was to correct the fields then click anywhere off the form so it would close.  Then select "New" again and the form would then save.  I had a couple of forms affected by that. 

I got a note from them yesterday stating that has been fixed.  So, you might try that first just to see if that helps.  If not, I'd delete the form and try again.  If that does not work, I'd look at how your dropdowns are set up since you should "normally" have no issue with saving. 

[#5]

I've used four cascading drop down list that's for four column respectively.
I've just found out that when I save the form an empty item is added and to confirm that if the item is added I've used ID column, even I can delete that item.

Any other suggestions to get the result from the drop-down list ?