what does it mean to have invalid contact data

Hi olamilekan129,

It appears you're looking for help because you're receiving an error message when attempting to import vCards. Is that correct? Also, can you tell us if you're receiving this error message when using the Contacts app on your Mac? If so, you're in the right place to receive support, and we recommend the following troubleshooting steps via the link below.

If an app can’t import vCards into Contacts on Mac - Apple Support

Please remember that the Contacts app exports contact information as vCard 3.0 files, but some apps don't accept files in this format. If an app can't import the vCards you exported, try changing the vCard file format, then exporting the vCards again.

To perform the troubleshooting actions we recommended via the article above, please read through and complete the steps in the section titled "If an app can't import vCards into Contacts on Mac."

We're recommending the steps above because the details we're providing will allow us to move our troubleshooting efforts towards a resolution by helping to resolve the issue you initially reached out to the community about, which is receiving an error message when attempting to import vCards.

If the original problem persists after trying the previous steps, please provide us with specifics on what you see for more help, and we will continue from there. 

We also noticed that you visited an article on your computer before posting, Limits for iCloud Contacts, Calendars, Reminders, Bookmarks, and Maps. Let us know if you have any additional questions we can assist with about that particular article. Please do not include any personal information in your reply if you do.

Thanks for using the Apple Support Communities.

Cheers!