I think common law and conjugal partners require two statutory declarations (meaning notarized written statements). Below I copied the letter I sent asking friends and family to write letters on our behalf. This may let a bit more helpful than one sample. The responses I got were quite varied...
Here is the letter I wrote to friends and family asking for letters of support...
Dear Friends and Family,
As you know I am seeking Permanent Residence status in Ontario, Canada through the Family Class immigration category. I am technically called a "Conjugal Partner" (nice and descriptive, isn't it?) and XXXX is my Sponsor. As part of the immigration application we are required to provide evidence that we are indeed a genuine couple. This includes written correspondence, passport stamps from visits to see each other, plane ticket stubs, photos, etc. We are also required to document the history of our relationship (which was kind of a fun exercise).
An important part of this evidence of genuine coupledom/coupleship, whatever you want to call it, is documentation from family and friends. My brother and his wife have agreed to make sworn testimony on our behalf, but from reading Canadian immigration blogs it appears that the more documentary evidence we can provide from external sources the more likely our application will be approved swiftly, or at least not denied on this basis.
So I am writing today to ask if you would write an email on our behalf and send it to me (or XXXX, if you prefer) by Friday. I realize this request is somewhat vague as to the content of the email, so I've included a list of basic points to cover at the bottom of this message. You are certainly welcome to write more, or less...whatever you are comfortable with putting in writing to support our Family Class application.
For those of you who respond, please accept my heartfelt gratitude for your timely assistance in this matter. For those who chose not to respond for any reason, please know that I accept your decision with much grace and goodwill.
Kindest regards,
Allison
General information to consider including in your message (this can be written in French or in English, by the way)...
1. A description of how you know either one of us (typically the person you knew first)...examples
I am a friend of XXX, I was a co-worker of XXX, I am the sister of XXX, etc
2. A description of how you became aware of our relationship, when you met the other partner, activities we participated in together, etc
3. A statement to the effect that, in your judgement, we are in a real, loving, ongoing, genuine (you choose the words) relationship based on your personal knowledge and experiences