I gave out my personal credit card info to a friend to order pizza online, should I be concerned? Are my personal info stored on his/her autofill phone?
Most of the legitimate keyboards on Android/iOS won't store credit card details for their "autofill" functionality. But if your friend has malicious intents and is somewhat tech-savvy, then you might have cause for concern. It is not difficult to get a keyboard(at least for Android), which can record keystrokes and then store them in a file, which can be later retrieved easily.
There are some other concerns as well, such as the portal where you entered your credit card information was secured or not, but I guess that'd be out of scope for this question.
Your safest bet would be to change your credit card password, which is used to make transactions. In case you neither have a password, nor the mandatory OTP facility for your credit card, it would be good to contact your bank and informing them that your credit card details have been compromised.
You should not concern only about autofill keyboard feature, the internet browser itself like google Chrome for example has the option to save the credit card information. What to do for your credit card security it depend on how your credit card provider deal with the online payment, some provider will send one-time password some other will redirect to additional web-based authentication then you need to change that password.