no option showing of facetime on my iphone4s

That is normal. Go to settings>facetime for the settings.

Select a contact and tap the facetime button to call the contact via factime.

Where was the iPhone purchased? If purchased in certain middle eastern countries, FaceTime has been banned and cannot be installed.

facetime does not need to be installed on 4s. There is no facetime app for 4s, but it is a part of the iOS and is activated as I decribed above.

Non the less there are countries, where the SIM lock locks the facetime as well.

No, the Sim does not lock FaceTime. It is permanently blocked on iPhones sold in countries where it is banned by the government. Changing a sim will not change that.

OMG. It is not the SIM but the lock profile, that is setup by the middle east carrier also disables the services like Facetime or for others Youtube etc.

As I stated above:

This is normal.

Go to settings>facetime to sign in.

Select a contact and tap the facetime button to call the contact via factime.

As your phone is from Canada and unlocked, there is no issue with the mentioned middle east countries!

If there is no FaceTime category under settings, go to Settings - General - About. What is the Model number?

...

Again, what is the model number?

my model no. is MD235AE, iphone 4s there is no face time pls help

my iphone 4s there is no face time pls help! model MD235AE.

I have a second hand iPhone 4s with iOS 7.1.2

No Facetime icon, no Facetime option under settings.

I thought the phone originally came from Spain, but it has been used in the Middle East.

Model MF266AE/A

Any suggestions? Thanks.