We bet on dividend companies to receive a future source of cashflow. There are many reasons, but one of them is they are usually more trustful (at least, in general, they have the money to pay dividends). Of course, these shares we buy don't have to be located in our own country of residency. Let's imagine that our plan is NOT TO SELL EVER and just to harvest their dividends. When we receive them, normally the countries where the stocks are placed get their taxes by withholding a part of the dividends.
The tables we attach below show the withholding rate on dividends IF NO TAX TREATY is active between two countries. For example, if a Spaniard living in Spain buys Jonhson & Johnson, he will receive the dividend minus 30%. However, as there is a double tax treaty between Spain and USA, if the Spanish investors fills in the W8 form (basically telling the US IRS he is non-resident in USA), he will receive the dividends minus 15% from the American side. On top of that, he will have to pay taxes in Spain for these dividends (15% already paid).
The tables we attach below show the withholding rate on dividends IF NO TAX TREATY is active between two countries. For example, if a Spaniard living in Spain buys Jonhson & Johnson, he will receive the dividend minus 30%. However, as there is a double tax treaty between Spain and USA, if the Spanish investors fills in the W8 form (basically telling the US IRS he is non-resident in USA), he will receive the dividends minus 15% from the American side. On top of that, he will have to pay taxes in Spain for these dividends (15% already paid).