The company opened its doors at East Midlands Airport in September 1997 and now has 25 offices around the world.
To mark the anniversary, the 25th shipment of every month was awarded a bottle of Champagne, and HAE is sponsoring the 25th dog pen at an animal rescue centre in the UAE.
Individual staff challenges and pledges include marathons, virtual walking the length of the UK, weight loss, charity giving, planting trees and plants, enjoying new drinks, eating vegan food, and trekking.
The final challenge will take place on 17 September when a team will attempt Yorkshire Three Peaks challenge within 12 hours, tackling the peaks of Pen-y-ghent, Whernside and Ingleborough.
The 15 team members will attempt the 24 mile route, which includes 1,585 metres of ascent, to raise money for Cancer Research UK, and have set themselves a fundraising target of £3,000.
A JustGiving page has been set up for the Three Peaks challenge, which can be accessed here.