I understand that you want to know more about integrating salesforce with external systems. It depends on which system you are trying to integrate salesforce with.You need webservices to integrate salesforce and other systems
Please follow the links below for more information
Start with the fundementals of Salesforce Integration. They are plenty of documents available in the Salesforce Library. The below link will explain the Integration concepts. https://developer.salesforce.com/page/Integration
There are two types of Salesforce Integration
Salesforce Inbound Integraion and Outbound Integration Salesforce Inbound Integration : If you want to perform Salesforce logics from External System. It means you need to go for Inbound Integration. You have to write your logics (Apex Code) and expose to the external system. External system will consume our code and will perform the Business logics. Salesforce Outboud Integration : If you want to perform External system logics from salesforc. It means you need to go for Outbound Integration. External system will share their code, we have to consume their code and will perform the business logics from Salesforce. These Integration can be done either by SOAP and REST. Please learn the concept of SOAP and REST as well.
I understand that you want to know more about integrating salesforce with external systems.
It depends on which system you are trying to integrate salesforce with.You need webservices to integrate salesforce and other systems
Please follow the links below for more information
https://developer.salesforce.com/page/Integrating_with_the_Force.com_Platform
https://www.salesforce.com/developer/docs/api/
https://developer.salesforce.com/page/Introduction_to_the_Force.com_Web_Services_Connector
Please let me know if this was helpful
Best regards
Naga kiran
Start with the fundementals of Salesforce Integration. They are plenty of documents available in the Salesforce Library.
The below link will explain the Integration concepts.
https://developer.salesforce.com/page/Integration
There are two types of Salesforce Integration
Salesforce Inbound Integraion and Outbound Integration
Salesforce Inbound Integration : If you want to perform Salesforce logics from External System. It means you need to go for Inbound Integration. You have to write your logics (Apex Code) and expose to the external system. External system will consume our code and will perform the Business logics.
Salesforce Outboud Integration : If you want to perform External system logics from salesforc. It means you need to go for Outbound Integration. External system will share their code, we have to consume their code and will perform the business logics from Salesforce.
These Integration can be done either by SOAP and REST. Please learn the concept of SOAP and REST as well.
Mark this as answer, if you find useful
Regards
Syed Moosa Nazir TN