Update lookup column in secondary list when a new item is created in primary list

[Ameen1989]

I have two lists Receipts and Users. Both of these lists are independent, there only relation is a lookup field.

 The Receipts list contains the purchase information of a product a user bought. Here are a few columns
- Payment Received
- Amount
- Name
- Receipt No.

The Users list contains the user information. Here are a few columns
- First Name
- Last Name
- Email
- Membership Type
- Receipt No. Lookup

Here is what I have accomplished so far.
1. The User lists already has the information included, except for the receipt no. lookup column, that is blank because they have not made a purchase. (this is done)

2. The value in the lookup column in the Receipt Lists needs to update if a user makes a purchase. So, when a user for example, User A makes a purchase, that information will be stored in the Receipt List and will also generate the Receipt No. (this is done)

Here is what needs to be done
When User A makes a purchase, a flow should run, updating the Receipt No. Lookup in the User List.

I am not sure how to copy the Receipt No from the Receipt List to the Receipt No. Lookup Column in the User List

[SudeepGhatakNZ]

@Ameen1989 ,

1. Add a trigger on the User list,
2. Add an action to create item in the Receipts list
3. The create item returns the ID of newly created receipt in ID field.
4. Set Receipt No field in User list to ID from the previous step

[annajhaveri]

@Ameen1989  when user makes a purchase, in which list is the item added, Receipts list?

[Ameen1989]

@annajhaveri 

Yes the receipts list. Once the item is added in that list, a flow must run which will automatically update the Receipt No. Lookup Column in the user list.

[Ameen1989]

What kind of trigger on the user list?

A flow is already made for that and the item get created in the receipts list. When the item is added in the receipt, it populates the Receipt No. column. I want the value in this column to update in the User List Receipt No. Lookup column

[annajhaveri]

@Ameen1989  you need a link between Receipts list and User lists, to fetch that specific user's item from Users list. Who creates the item in the Receipts, is it that user itself?

[Ameen1989]

There is already a link created and that is the Receipt No. Lookup column in the User list.

Are you saying that I need to add a lookup column in the Receipt List as well?

So, right now there is a link between Receipt and User list and now I have to create a link between User and Receipt List?

[annajhaveri]

@Ameen1989  but you still need to update receipt number in User list, how will you find for which user record you will update that Receipt Number, so i think you need user details in Receipt list, if user itself is creating item in Receipts list, then you can use CreatedBy column value.