My husband and I have thousands of pages of chat history (we have known each other since 2009). We exported everything to a word-compatible format since we could make the font smaller and still readable with less wasted space than with screenshots of apps, and then we excerpted the important bits. The maximum is 10 pages, so you'll have to really pick and choose to keep it under that limit. We aimed for picking the real emotional bits of our conversations (tear-jerkers and/or sweet parts, like if that part of the conversation was in a movie/show, they would be memorable lines), and conversations that discuss really important things (parents being hospitalized, mental health, etc.). We sampled so that there was some conversation from every year of us knowing each other to support that we have been in constant communication this whole time.
Our situation was considered a "complex" case (PA has criminal charges, plus we have some red flags in our relationship according to IRCC standards - age gap greater than 10 years, PA and sponsor are different ethnicities, PA has been married once before but sponsor has not), so we submitted 40 pages of chat logs and another 5 pages of call logs as proof of our relationship (our lawyer said this is okay in our application since we are not a straightforward case). However, if your case is not complex, you should definitely try to keep within the 10 page limit and not overwhelm the IRCC officers processing your case too much.
