Hi

This does not sound like an offer that has legitimately come from Firefox.

I do not know who the "they" that you refer to is, but I recommend that you go back to them for help with this issue and to make sure that you have not been caught up in a scam or fraud.

stphnntambi said

They have sent me an offer of getting Samsung S10 today on 16th September 2019. Am in Uganda and I don't have a zip code or a visa card. How best can I get this offer . Am a Firefox user and lover, help me please.

This was a "Too good to be true" scam trying to prey on people who will give up their personal details like name, email, phone#, credit card information (for the extremely cheap shipping) and such information for a prize that does not exist.

It does not make sense for Mozilla to pick random Firefox users and say they won a insert Samsung, iPhone or a Amazon gift card that are worth say $1000 US and have this on some random weird name website.

If Mozilla were by chance give out random prizes to Firefox users, it would be on say a *.mozilla.org page.