Hello @Karolina Kaźmierczak
Azure subscription 1 is default name when a subscription is created. At any point in time you can follow the steps given in below document section to rename your subscription as per your convenience.
Doc reference link: https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/change-azure-account-profile#change-the-subscription-name
Nevertheless, subscription name is just for identification and it doesn't have any impact.
Hope this clarifies.
Regards
Divya.