Care instructions can be found on the garment label and on the product page. Always follow the instructions on the label for that specific item.
General guidance
The garment label is the authority, but as a general rule:
Wash inside out to protect prints, badges and embroidery.
Use a cool wash and a gentle cycle.
Wash with similar colours.
Avoid bleach and harsh detergents.
Avoid tumble drying where the label advises against it, as heat can damage prints and cause shrinkage.
Do not iron directly onto a printed graphic or badge. Iron inside out, or place a cloth over the print.
Do not dry clean unless the label specifically says you can.
Caring for a garment correctly also matters for returns: damage caused by washing contrary to the care instructions is not treated as a manufacturing defect.