Integration of ISO 9001 and ISO 14001 become much easier with new revisions of both standards, similarities spread throughout most of the clauses and the clause numbers are the same for common requirements.
Here are the similarities and how they should be met:
clause 4 Context of the organization - Both standards require context of the organization to be identified, along with internal and external issues relevant to ISO 9001 and ISO 14001. The requirements of both standards can be met in a single document (e.g. Procedure for Determining the Context of the Organization and corresponding records).
clause 5 Leadership - Each standard requires appropriate policy to be established, but the requirements for Quality Policy and Environmental Policy are different so it would be better to have separate documents, but it is not a mistake to create one policy for int egrated management system.
clause 7 Support - This clause has the same requirements in both standards so, only one procedure for competence training and awareness will cover the requirements of both standards, as well as the Procedure for Document and Record Control. The only thing to be mentioned here is, when creating the procedure make sure that you stated that the scope of the procedure is integrated management system and in reference documents section list both standards.
clause 9 Performance evaluation - Requirements that can be merged from this clause are internal audit and management review. Since the process of internal audit and management review are the same for both standards, the same procedure can apply for both standards. Only thing that is different are the requirements to be audited during the internal audit so different checklist should be kept but the Procedure for Internal Audit and the rest of the records can be used for both standards, and also for management review the same procedure can be used only the input and output elements are different so Management Review Minutes can be kept separately or merged in one record.
clause 10 Improvements - Nonconformities regarding different standards can be resolved by the same corrective action process, therefore the same Procedure for Managing Nonconformities and Corrective Actions can be used for both standards.