Documentation:
https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/intro_understanding_web_server_oauth_flow.htm


Method:
POST

URL:
https://login.salesforce.com/services/oauth2/token

Header:
Content-Type: application/x-www-form-urlencoded

Body:
grant_type=password&client_id=3MVG9HxRZv05HarTyunhC4dHwrkILJSnBtbdnHbPnnzgN1CPb_afTZ43K9E9LAi9UbStGPl6ZdPiYUkD81kl6&client_secret=6312532765104039215&username=ronen.cohen@poalim.co.il.lab&password={{passworkd+APIKey}}

Response Example:
{
	"id":"https://login.salesforce.com/id/00D50000000IZ3ZEAW/00550000001fg5OAAQ",
	"issued_at":"1296509381665",
	"instance_url":"https://na1.salesforce.com",
	"signature":"+Nbl5EOl/DlsvUZ4NbGDno6vn935XsWGVbwoKyXHayo=",
	"access_token":"00D50000000IZ3Z!AQgAQH0Yd9M51BU_rayzAdmZ6NmT3pXZBgzkc3JTwDOGBl8BP2AREOiZzL_A2zg7etH81kTuuQPljJVsX4CPt3naL7qustlb"
}