Providing (that) is more common in speaking; provided (that) is more formal and more common in written language:
[talking about rail travel in the UK]
You can get a senior citizen’s reduction providing you’ve got a railcard.
They may do whatever they like provided that it is within the law.
Although occasionally still disapproved, providing is as well established as a conjunction as provided is. Provided is more common.
The phrase “providing that” is sometimes used as an alternative to “provided that”. Both mean the same thing and both are correct, but “provided that” is the more popular alternative.
The words provided and providing are interchangeable when used to mean on condition that.
Provided that the weather is fine, we'll have a picnic on Saturday.
Providing that the weather is fine, we'll have a picnic on Saturday.
Some writers maintain that provided is preferable to providing as a conjunction meaning on condition that. Both are acceptable. However, as some of your readers may prefer provided, it is safer to choose this option.
The conjunctions Provided that and providing that can interchangeably be used to mean "if - on condition that"