After completing the prologue of Red Dead Online, you will get access to the game's every online feature. Go to a stable - there, you will be able to purchase a horse. Red Dead Online has an option that wasn't available in Red Dead Redemption 2 - you can buy horse insurance.
Where can I buy horse insurance?
Players in Red Dead Online can be really aggressive. It is highly probable that your horse will get shot or killed - even from a long distance. The developers have introduced horse insurance which can be purchased at every stable.
What does horse insurance offer you?
Thanks to horse insurance, a critically wounded horse will regenerate after some time. If, for example, your horse got shot, it will stand up after some time and have its health full again. Without horse insurance, a "dead" horse must be retrieved from a stable - you will also have to pay $4.
How much does horse insurance cost in Red Dead Online?
The first horse insurance is free (at the moment of writing this guide which is based on the beta version), so you should definitely get it. Sadly, consecutive horse insurances cost 5 gold bars. This is quite a lot, especially when you have just started playing Red Dead Online. Better wait with buying it, i.e. once you get a really good horse.