Montreal is the metropole of the Province of Québec, in Eastern Canada.
The main point of entry to Montréal by air is the Pierre-Elliot Trudeau International Airport (YUL), located in the Dorval suburb, 20 km west from downtown Montréal, where McGill University is located.
See "Local Transportation" for how to reach the city center.
Most colleagues should require only an eTA to enter Canada, but a visa is required for some others e.g. if their countries are also asking for visas from Canadians, such as Russia or China. Please check the lists carefully to determine your situation.
Should you need a letter of invitation to join to your visa application, please let me know as early as possible by writing to firstname.lastname@example.org.