Display another list fields in popup and save within single form

[Margo]

Hello @harshp924,

You can filter items in List or Library control dynamically. Please see this post from more details:

Showing List or Library control data to show only one row of data base on person name

Hello @lso, You can filter records in List or Library control dynamically using CAML query. You can find the example in the documentation here. Note that to filter 'Person or Group' field by user name you need to set the 'Value Type' to be qual User <Contains><FieldRef Name='ColumnName'/><Value Type='User'>Jane Doe</Value></Contains>