Good morning, @Sajiidach most plans with Fido include free international texting from Canada to other countries. You can check the links in @Cawtau 's post above for more information about international texting. Basically if you have a monthly plan then you have international texting from Canada to other countries. But, please check the links above for reassurance
Welcome to the community!
Firstly, what do you mean by International texting? Do you mean sending a message to an International phone number from Canada? Or do you mean sending messages while you're outside of Canada?
What plan do you have? Most newer plans include International texting. That is, sending messages to International phone numbers from Canada. Some plans limit the number of included messages and some older plans may not include International texting. You should be able to view the details of your plan via My Account.
On the other hand, if you mean sending messages while you're outside of Canada (ie texting in UK and UK to Canada), that is considered Roaming and would incur additional charges. If you have a postpaid plan, you would most likely be travelling with Fido Roam (ie did not opt-out). You will be charged $12 per day (assuming UK) if you use your device to make or receive a call, send a text message or use data while abroad. If you opted-out of Fido Roam or have a prepaid plan, it would cost 75¢ per SMS message. MMS messages would also incur roaming data charges (not available on prepaid).
Hope this helps