I’m not sure this is the right place for this question.
I have some first day cover stamped envelopes. I don’t know much about them. Or what to do with them, is this something that is for a collector or do people use them as regular envelopes? What would be the reason someone has first day cover envelopes? I feel kind of dumb for not knowing 
This is just a few that I took pictures of. Sorry for the Terrible lighting!
They are a collectors item. 
First Day Covers are mainly for collectors. They are a bit like maxicard: matching picture on the envelope, stamp and special first day cancellation. Our mail services have not made maxicards for a while, but they make First Day Covers. I have a few pretty ones in my collection. Some collectors don’t want uncancelled (mint) stamps and First Day Covers have great specially designed hand cancellations. Just like in your hare envelope. They carefully cancelled the stamp so one can appreciate designs of both the stamp and cancellation. Often the stamp artist designs the envelope too.
First Day Covers are seldom used as envelopes as the stamps are already cancelled. In Finland you ought to add more stamps to mail them as they are and that would ruin the philatelic value, I am sure. I have received some letters in First Day Covers from abroad ages ago. I am not sure if they were mailed on the day of issue or if some countries allow them to be used without extra postage, but they look great and I have saved them.
In UK we can buy envelopes decorated with a current stamp release image. You can then put mint stamps on them and post. Fun if you want to send a letter or other items but wont have the pretty postal marks mentioned above.
That’s really cool!
They are for collectors.
I have just bought this one:
It commemorates Frantisek Behounek, who was was a Czech scientist (radiologist), explorer and writer.
People collect stamps affixed on envelope with date cancel of release date and it becomes collectors’ item by time,
And it’s known as FDC (first day cover)
Mostly they are unused(without address) or used on day of release with address
Few of my FDCs
First Day Covers fall under the category of “Postal History” which is a very not area among collectors. I have several thousand in my collection. Historically in the United States, FDCs were produced by many different private company cachet makers (the cachet is the illustration); many of these are quite worthless since very large numbers were produced in huge numbers. The bottom three covers you show don’t have a cachet; collectors stay away from these. Some though are sought after like hand-painted cachets.
In other countries, FDCs are primarily issued as “Official” - that is, by the Postal Authority of that country. I only collect "Official FDCs. Above you can see some examples in my collection. Enjoy.
Thank you for explaining the difference between the two types I have.
Question:
Does anyone collect covers other than First Day of Issue or Pictorial Postmarks?
If so what type of covers and could you post an example?
The following cover is an example of something I am doing.
The subject of “covers” is very broad. First Days are popular; I have a large number of European FDCs in my collection. But there are other types that are popular too. For example, you can have event covers; first flights are a good example. Another popular area are Space Covers. I have posted some examples of covers that I found interesting, including a censored cover and a mourning cover (JFK). With each of them, a story is told.
