This can vary enormously depending on where you apply and the type of application.  If the business is already registered as an E2 Treaty Investor business this should make it quicker and easier.  The processing times at US Embassies and Consulates to register an E2 visa business varies greatly around the World.  Some may be able to complete applications in a few weeks.  Others could take a number of months.  If you are able to apply from within the US, applications made directly to the USCIS in the US can be fast using premium processing.  However, not necessarily recommended.  Please note that due to COVID-19 there may be significant delays in processing times.