I'm looking for curl sample for getting api_token shown below

curl -v -X GET \
-H "Accept: application/json" \
-H "Content-Type: application/json" \
-H "Authorization: SSWS ${api_token}" \

I already tried OKTA UI but will need eventually to get token value programmatically.
Also, how to understand this “Okta uses a bearer token for API authentication with a sliding scale expiration. Tokens are valid for 30 days and automatically refresh with each API call. Tokens that aren’t used for 30 days expire. The token lifetime is currently fixed and can’t be changed for your organization.”. Let’s say I want to have the sake token for about a year, how can I do that if I use one created using OKTA UI for our organization?
Your help will be greatly appreciated