Slack

This one isn't particularly ancient, but it scarcely needs an introduction. Even if your team does not use Slack, I'm sure you've heard of it. Slack serves as a centralized communication center for teams of various sizes.

Slack's communication is strengthened by powerful features such as:

• Drag-and-drop support for documents, pictures, videos, PDFs, spreadsheets, and other file types into the application

• Conduct group and individual conversations to separate topics and discussions for rapid and confidential communication.
• Carry out voice and video calls with up to 15 people at once.
• Share your video screen for a more productive and transparent conversation.
• Search any document, message, or chat in seconds.
• Configure notification settings to meet your specific requirements. Select and deactivate notifications from

Pricing: Free/ $6.67 per user/month

Top Feature: Messaging

Platforms: Web, Android, iOS

Website: Slack.com