If plans are required to be submitted to the City, then a Site Plan Review application must be submitted to the Planning Department to start the review process.
Plans must be drawn by a licensed architect. A draftsman may also draw plans for small work. See this document to determine if a licensed architect will be required to draw your plans. A floor plan of the existing property conditions and proposed changes are required.
Contact the Planning Department at (310) 973-3230 to verify what additional details will be required to be on the plans.