In today's digitally interconnected world, one's ability to collaboratively create with others and compose multimodal texts is essential. Yet, high-stakes standardized assessments that value individualistic print centric conceptions influence instruction, leading schools to often undervalue the multimodal and collaborative composing processes and products necessary for success in the 21st century. Through three papers, this dissertation explored collaborative and multimodal composing in terms of how it has been studied by researchers and how it was enacted by third-graders participating in remote school. First, a systematic literature review, critically examined collaborative writing research, in terms of the studies' characteristics, data sources, methods of analysis, and findings. The studies mostly involved adult learners writing in the non-fiction genre and found that writers tended to use cooperative processes, which were influenced by tools, genre, and group dynamics. The review also underscored the need for diverse, multimodal research approaches to understand collaborative writing more effectively. Next, I present an empirical study that considered third-graders' collaborative writing processes in a shared Google Doc. Here, the groups used different styles of idea development, unitary and parallel, was shaped by how each group participated within and across digital spaces. The final paper analyzed third-graders' multimodal collaborative writing inside of Google Slides, by focusing on their changing patterns of joint attention. It revealed how joint attention supported content creation, organization, and technical skill sharing, highlighted the fluidity between individual and shared focus, and the role of different interaction modes across their process. Together, this dissertation advocates for comprehensive data collection and multimodal analysis to understand collaborative processes fully, integration of collaborative and multimodal tasks into writing instruction, and an expanded view of writing as a collaborative, multimodal process. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]