The new application should state that your mother-in-law is funding some (or all?) of the costs, explain why she’s doing that, and provide her bank statement to show where the deposit came from. Use the section at the end of the application, to explain the background to the transfer of funds that led to the refusal. If your mother-in-law is travelling with you, include that in the application too. The first refusal will also need to be declared. From your first question https://travel.stackexchange.com/questions/116283/reapplying-for-uk-visit-visa it appears that your entire family will be travelling; this could be a red flag unless both you and your husband can prove strong ties to home.

The new application should state that your mother-in-law is funding some (or all?) of the costs, explain why she’s doing that, and provide her bank statement to show where the deposit came from. Use the section at the end of the application to explain the background to the transfer of funds that led to the refusal. If your mother-in-law is travelling with you, include that in the application too. The first refusal will also need to be declared. From your first question https://travel.stackexchange.com/questions/116283/reapplying-for-uk-visit-visa it appears that your entire family will be travelling; this could be a red flag unless both you and your husband can prove strong ties to home.