Traditionally "Import - Export" was a trading sector in it's own right. Today with increased globalisation and the differences in cost between countries, many companies not acting solely as import agents are sourcing manufactured goods from places such as Brazil, China, Eastern-Europe and India.
There are however numerous regulations that vary according to the goods place of origin and the type of products involved. The shipping and distribution costs also will vary depending on quantities and locations. It's essential that all of this is understood well and you start from the beginning in including the associated costs in your business plan.
It's much easier also to clear all the forms and regulations upfront, as without such, you'll at best delay your shipments and maybe even face addition costs or fines.
With Exporting goods you will of course have done a thorough market research of the area that you are targeting. That area will undoubtedly have their own Import regulations, so you also need to investigate those as well as your own country's export requirements.
It's a broad subject but one of the best on-line resources we've found are these pages at Business Link:
On-line guide to Import and Export