Share a contact, not your whole address book entry
When you share a contact from your phone, it often includes everything: home address, personal mobile, birthday, notes you wrote about the person and their photo. Open the .vcf here, tick only what the other person should get, and save a clean copy.
Sensible defaults
Name, company, job title, work phone, work email and website are kept. Home addresses, personal numbers, birthdays, notes, photos, locations and app IDs are left out until you tick them.
How to get a .vcf file
iPhone: Contacts → open a contact → Share Contact → Save to Files. Android: Contacts → open a contact → ⋮ → Share → as a file. Google Contacts: select → Export → vCard. Outlook: open the contact → File → Save As → vCard.
Questions
Is the contact uploaded?
No. It's read and rebuilt in your browser.
Can I clean several contacts at once?
Yes. A .vcf with many contacts shows each one, and "Name and work only" resets a contact to the defaults.