Hello Joan,
After signing up for iTunes Match, you won't need to use iTunes to sync your music, but you can still transfer your purchased apps from your iPhone or download them directly from the iTunes Store.
If you want to transfer the apps to your computer, follow these steps:
iTunes Store: Transferring purchases from your iOS device or iPod to a computer
http://support.apple.com/kb/HT1848
I find it convenient to download my purchases to iTunes directly from the iTunes Store. If you would like to download your purchases that way, follow the steps in this link:
iTunes 11 for Windows: Download previous purchases from the iTunes Store
http://support.apple.com/kb/PH12491
To avoid following these steps each time you make a purchase, you can enable Automatic Downloads using the steps in the section titled "Enabling Automatic Downloads on your computer" in the following article:
iTunes Store: How to enable Automatic Downloads
http://support.apple.com/kb/HT4539
Thank you for using Apple Support Communities.
Best,
Sheila M.