Open adoption
The birth family and the adoptive family know one another and agree on contact. That might be photos, messages, calls, or visits. You decide the pace together and write it down. Full names and addresses are shared only if both sides agree.
Semi-open adoption
Letters, email, and sometimes a visit pass through the agency. The families may know first names and still keep phone numbers and street addresses private. This can offer news of the child without a direct relationship.
Closed adoption
No identifying information is exchanged. Some birth parents choose this for safety, including when a relationship has been violent. Others choose it because they want a clean break. Closed plans are less common, and they are still done when they are the safer choice.