Need to change color of a texture

It can be done with shader coding. When you use build-in standard shaders you can write your own shaders. in this case you can simple write a surface shader like this and apply the albedo and mask texture:

 Shader "Custom/MaskShader"
 {
     Properties
     {
         _Color ("Color", Color) = (1,1,1,1)
         _MainTex ("Albedo (RGB)", 2D) = "white" {}
         _MaskTex("Maks (RGB)", 2D) = "white" {}
         _Glossiness ("Smoothness", Range(0,1)) = 0.5
         _Metallic ("Metallic", Range(0,1)) = 0.0
     }
     SubShader
     {
         Tags { "RenderType"="Opaque" }
         LOD 200
 
         CGPROGRAM
         // Physically based Standard lighting model, and enable shadows on all light types
         #pragma surface surf Standard fullforwardshadows
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _MainTex;
         sampler2D _MaskTex;
 
         struct Input
         {
             float2 uv_MainTex;
         };
 
         half _Glossiness;
         half _Metallic;
         fixed4 _Color;
 
         // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
         // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
         // #pragma instancing_options assumeuniformscaling
         UNITY_INSTANCING_BUFFER_START(Props)
             // put more per-instance properties here
         UNITY_INSTANCING_BUFFER_END(Props)
 
         void surf (Input IN, inout SurfaceOutputStandard o)
         {
             // Albedo comes from a texture tinted by color
             fixed4 c = tex2D(_MainTex, IN.uv_MainTex)*(1-tex2D(_MaskTex, IN.uv_MainTex)) + tex2D (_MainTex, IN.uv_MainTex) * tex2D(_MaskTex, IN.uv_MainTex)*_Color;
             o.Albedo = c.rgb;
             // Metallic and smoothness come from slider variables
             o.Metallic = _Metallic;
             o.Smoothness = _Glossiness;
             o.Alpha = c.a;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }
 

Here are some learningresources:

Unity manual about writing surface shaders Unitys overview of writing surface and vertex/fragment shaders

If you are using different renderpipelines like URP or HDRP there is a free visual shader programming tool from Unity called ShaderGraph.

Unity Shader Graph introduction

A good tool in current build-in renderpipeline for people with less knowledge on shader programming to understand and learn shaderprogramming might be a visual shader programming tool like Amplify Shader Editor.