Hi Deriv Community Member,
The Martingale strategy is a classic trading technique that encourages traders to double contract size after a loss so that when they do win, they will regain what they have lost.
To use this strategy on your Bot, go to the “Bot builder” and click "Quick strategy” 
Select Martingale strategy
You may edit the parameters accordingly and click “Edit” to further check on the strategy. Otherwise, you may click “Run” to automate your trades.
To know more about quick strategy, please refer to this topic: Simple Steps in Setting Up Quick Strategy in Dbot
If you have any questions, please visit our Help Centre or contact us via Live Chat and WhatsApp.