When going to France Dover - Calais is the most common route to go on. You have P&O's ferries and the Eurotunnel. Some people like one, some like the other. This page describes some differences.
On the Eurotunnel it goes from Folkestone to Calais roughly. At the Folkestone terminal it is part owned by the channel tunnel and part owned by Welcome Break, MSA operator. Luggage is more limited and it's more expensive but takes less time. You can also bring your car onboard which is put onto the back. Travelling with pets may be limited.
Now you might have made your mind up if you're travelling to France.
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