A 90-day digital marketing course can be an intensive program that covers various aspects of digital marketing. To give you an idea of what topics you might consider including in such a course, here's a sample outline:

Week 1-2: Introduction to Digital Marketing

Understanding the digital marketing landscape
Setting marketing goals and objectives
Conducting market research and identifying target audience
Creating buyer personas
Week 3-4: Website Optimization and SEO

Website fundamentals and best practices
Keyword research and on-page optimization
Technical SEO and website performance optimization
Introduction to off-page SEO and link building
Week 5-6: Pay-Per-Click (PPC) Advertising

Introduction to PPC advertising (Google Ads, Facebook Ads, etc.)
Keyword research for PPC campaigns
Creating effective ad copy and landing pages
Optimizing campaigns for better ROI
Week 7-8: Social Media Marketing

Understanding different social media platforms and their audience
Developing a social media strategy
Creating engaging content for social media
Using social media analytics and metrics
Week 9-10: Content Marketing

Creating a content marketing strategy
Writing compelling blog posts and articles
Content promotion and distribution
Measuring content marketing success
Week 11-12: Email Marketing and Automation

Building an email list and segmentation
Creating effective email campaigns
A/B testing and optimization
Marketing automation and lead nurturing
Week 13: Analytics and Reporting

Introduction to web analytics (Google Analytics)
Setting up tracking and goals
Analyzing data and generating reports
Using data to make data-driven marketing decisions
This outline provides a general structure for a 90-day digital marketing course, but you can tailor it to meet specific needs or include additional topics based on the level of expertise and interests of the participants. It's also essential to include practical exercises, case studies, and real-world projects to give participants hands-on experience and reinforce the theoretical knowledge.