If your SSIS Package is deployed using Project Deployment Model and it SSIS Package is executed inside SQL Agent JOB then perform the following steps to export log in Excel format.
- Open SSMS (SQL Server Management Studio).
- Navigate to following node (Your Server> Integration Services Catalog > SSISDB > YourFolder > YourProject > YourPackage).
- Right click on Package > Reports > Standard Reports > All executions like below.
- Once Report is visible you can click on "All messages" link
- Inside Report right Click > Export > Excel like below