If you can't prove common law, then her options start becoming more limited.
She can come as a visitor. She should be allowed in for six months (up to the officer how long she is allowed in for) and can then try to extend her visit. However as a visitor she won't be allowed to work at all and won't qualify for benfits such as provincially funded health care.
If she can secure a full time job from an employer in Canada, she can come on her own work permit. To hire her, the employer will have to prove the job was advertised and no Canadian could be found for the role. The employer will also have to pay a $1K processing fee for this priviledge. (There is no self employed work permit available. She would need to find an employer.)
She could attend college or unversity in Canada and come on a study permit (although there's probably not enough time to be accepted into a college or university program and also obtain a study permit by September - so probably not a realistic plan until January). If she considers doing this she should look into the foreign student fees. They are quite high.
There is also the IEC program (International Experience) which is a working holiday visa. If she is young enough she might qualify for that. The problem with this option is that all of the spots for this year were gone a long time ago. When the program re-opens in January, spaces will go very quickly and it may be challenging for her to secure one. Also, in the event she is accepted, it will take another few months before the visa is actually ready (likely March or April).
You could also get married so that she can qualify for an open work permit as your spouse.