I have two vCenter Server: one for Horizon and one vCenter for other VMs like mail server etc. I have license for vROPs and it is integrated with second vCenter. Can I integrate the same vROPs with vCenter for Horizon or I must buy special license? Licenses for the "normal" environment can cover the Horizon environment?
You should have a vRealize Operations for Horizon License.
After installing the Horizon Adapter you have to license it and assign the license in the Horizon Solution License Group.
And other information that may be useful for you, from the EUC Packaging and Licensing:
vRealize Operations for Horizon requires two license keys to work: vRealize Operations Manager key and an Adapter key. vRealize Operations Manager license key quantity will be a quantity of 1 regardless of whether it is sold in a 10- or 100-pack. The Adapter license key quantity should align to either 10 or 100, corresponding to the pack purchased. In the case of vRealize Operations for Horizon as part of Horizon Enterprise Edition, the existing Horizon Suite key is leveraged as the Adapter license key, so it aligns with the appropriate pack quantity, and vRealize Operations Manager license key is fulfilled at a quantity of 1 for each 10- or 100-pack.