How to make a transparent background white for an image using Powerpoint

You need to use the fill function

Double click the image, Format Picture panel -> Fill -> choose white color

how to sync/link/share contacts between different Google/Gmail accounts?

You can export and import contacts.

1. Go to google contacts: https://contacts.google.com/
2.Use the export to save your contacts
3. log on to your other account
4. use the import to load your saved contacts

How to change siri voice

settings -> siri & search