Please read the guide, which can be found on this page http://www.cic.gc.ca/english/information/applications/guides/EG7TOC.asp
It won't take too long to read. After reading it, if you have queries you can ask.
For applying you will have to arrange/collect documents like
1. Passport copy, National ID copy, Birth certificate copy
2. IELTS (general training - original result has to be submitted- not photocopy)
3. SSC HSC MBBS etc degree certificates, mark sheets, transcripts needed for you and wife
4. contract letter/appointment letter, experience certificate/reference letter from the hospital
5. marriage certificate, nikahnama to prove marriage
6. Bank certificate to show proof of funds.
7. Police clearance certificate of Bangladesh and other countries where you/wife lived for more than 6 months
8. All completed, signed, dated application forms
9. Bank draft of $1100 for you and your wife.
10. All photocopies have to be notarized. If any document is in Bengali, it needs to be translated by registered translator in translation centers letter pad, and then translator also has to provide sworn affidavit stating that the translation made by him/her is accurate and truthful.
There are many other things to be done, you will know more once you read the guide in the link mentioned. After that if you still have doubts, you can ask. It will be easier for you to understand if you have a good idea of the steps involved.
Best wishes for your upcoming journey.