What role did Britain's colonies/colonial populations play in WW1?

The colonies of Great Britain played a significant role in the war effort during World War I. Soldiers and laborers from every part of the British Empire took part in the conflict. India alone provided one and a half million soldiers. Many also came from New Zealand, Australia, North Africa, and the Caribbean. People from these colonies took part in nearly every major campaign of the conflict, either as support personnel or as combat troops.
Many people from the colonies worked building fortifications and transporting supplies. Most of these support individuals were not members of the military but served a crucial and often unappreciated role in supporting the war effort.
When it came to joining the armed forces, New Zealand and Australia saw a large number of its young men rush to enlist in the Australian and New Zealand Army Corps (Anzac). These soldiers saw heavy action fighting the Ottoman Empire in the doomed Gallipoli campaign. Many Indians and North Africans served in France and other places along the Western Front.
Geographically, the British colony of Egypt played a large role in the fight against the Ottoman Empire. Since it bordered the Ottoman Empire along the Suez Peninsula, the British were able to use Egypt to send over supplies and personnel in order to aid the Arab insurgency that they were supporting.
https://www.telegraph.co.uk/history/world-war-one/inside-first-world-war/part-five/10542773/non-european-involvement-war.html