Hey @Preethi16 ,
In Power Automate Desktop you can execute Python, VB, and JavaScript code samples. I
Just Search for RUN on the actions blade -

In this example I am using PowerShell Code to Convert a File to a Base64 string, which we will use in the Invoke Web Service action.
[convert]::ToBase64String((Get-Content -path "C:\Users\ClavinFernandes\Desktop\clav.txt" -Encoding byte))

If this reply has answered your question or solved your issue, please mark this question as answered. Answered questions helps users in the future who may have the same issue or question quickly find a resolution via search. If you liked my response, please consider giving it a thumbs up. THANKS!