You can’t. This is set when the company is created and it can’t be changed after the company is setup and in use.

Can some one tell me at which point of the company creation this option is coming up ? Is it a setup or is this base on what you pick as the currency base ?

@Carlo Palma @ManilkaP This setting needs to be setup when creating the Currency Code in the company.

Accounting Rules\Currency\Currency Codes

However note the help text and proceed accordingly as not every currency code can be inverted.

Inverted Quotation  When Reference Currency
If this check box is selected inverted currency rate quotations will be used for the currency. This check box can only be selected for the currency that represents the company’s accounting currency, parallel currency and for EUR.

Thanks @Buddhika Kurera , so if I am creating the company by copying an existing company at which point do I update this ?

@ManilkaP I dont remember off the top of my head, if the Currency Codes are getting copied when you create a company by copying an existing company. Please check this.

Even so, currency codes can be created and deleted. You can try creating the currency code and if it exists, delete the existing currency code (as you cannot modify the invert flag afterwards) and create a new record with invert flag on.

Unfortunately, it does get copied.

That should work usually, but in my case it is the parallel currency. Even if I do delete it from the rate type since the code is used as the Ref Currency Code it doesn't allow me to delete the Currency code. 

@ManilkaP Yes it makes sense, I didnt consider that side.

Currency can be inverted, if and only if the Currency Code is EUR or Company Currency or Company Parallel Currency.

When copying from an existing company, it is not possible to change Company Currency and Company Parallel Currency. That means, unless the currency is EUR, this is not possible.