After logging in, you will be redirected to the settings page, where you can see the Account button at the top right.

https://desk.zoho.in/galleryDocuments/edbsne4c27e6f50e1500d12f048c536e3352264706ca19f4931db021a896cf719f21b2cb38bd5ad6c6cd046c1d6ab46b170f86c318646671e0a7e68b2a13502b71266?inline=true

Then, you can find the Subscribe button on the left side.

https://desk.zoho.in/galleryDocuments/edbsne4c27e6f50e1500d12f048c536e33522eb1868c681fc07306266cc981883c816aec41cb02ff6e4c339b93425ed0fcf7c040e6c7916ae3f073ae401698cb411f8?inline=true

Here, you can buy a plan.