Most countries tax two things: gains when you sell shares for more than you paid (capital gains), and dividends when they are paid out. How much, when, and on which accounts differ a great deal between countries - this page explains the general ideas, not the rules where you live.
Common principles
Losses can often be set off against gains. Some countries tax gains only when you sell (realisation), others tax the yearly change in value. Special savings or pension accounts may have lower tax or tax deferral, often with limits.
Get it right
Check your national tax authority's guidance or ask a qualified tax adviser. Ticker Picker does not give tax advice.
This content is general information, not investment advice.