Log into your HubSpot account.
Go to Settings > Account Setup> Integrations > Private Apps.
Select Create a private app.
In the Basic info page, add name as Zoho-crm-migration and add a description.
Click the Scopes tab. Select the following from the list of scopes:
crm.objects.contacts.read
crm.objects.companies.read
crm.objects.deals.read
crm.objects.owners.read
crm.objects.quotes.read
crm.objects.line_items.read
crm.objects.owners.read
e-commerce
Click Create app button in the top-right corner.
In the Create a new private app popup, click Continue creating to generate an API key.
To migrate data from HubSpot

If a record has more than 10 tags, only the first ten tags will be migrated.