Search Help is essentially a value help / lookup mechanism that helps users find and select valid values for a field.
When you see the F4 help in SAP GUI or the value help dialog in Fiori apps → that’s driven by Search Helps.  

Steps to Create Search help Using CDS View.

Step1 : create a CDS view

Step 2 : GOTO SE11 –> Search Help In selection method add the CDS view SQL view name.

Step 3 : Append it in the collective search Refer to the Append structure to add the elementary search in collective.

Test:

Step 4 : In the collective search after append the structure we can call it in the program

We have successfully created A search Help using CDS View.