ISOFIX refers to the international standard for the attachment points for child safety seats in cars.
In the US it’s often referred to as LATCH (Lower Anchors and Tethers for Children).
Cars fitted with ISOFIX attachments will normally have anchor points at the base of the rear seats, along with points above and behind the seats.
Most child car seats are designed to work with these anchor points which makes for fairly easy, secure installation.
Things to be aware of: