Need help

Please review the Arduino hardware pinouts and their designations

It looks like the second 'if' should be an 'else if'.

if 
else if
else

instead of

if
if
else

Otherwise the pin is being turned on by the first if and then immediately turned off by the else.

'B1' versus 'BI' seems strange, not sure if it's related.

Also, just as an idea,  it would be simpler if you just wrote one third of the code (i.e. for one pair of buttons) and tested and got that running first, because then you can scale it or rewrite it.

It should really be prototyped on breadboard with a couple of LEDs and resistors, so that you can be sure your code is working fine before subjecting it to the motors. If you're seeing 1V on pins, then you've got hardware issues (as well as the code issues).

Also, (I'm being blunt because you won't get far without a lot of help from others, unless you make this effort), you really should study C, because the code is really not pretty (clue: too many variables, and too much code that could be collapsed and simplified).

i got somekind of error when i had it as B1 

i made some changes to the code but now i get 5v from D2 and only 2.9v from D3. the funktion im after is, if B1 is HIGH then D2 must be HIGH and D3 must be LOW. and if B2 is HIGH then D2 must be LOW and D3 must be HIGH

 //B1-B6 Buttons 
 //D2-D7 output pins
 
int BI = 14;
int B2 = 15;
int B3 = 16;
int B4 = 17;
int B5 = 18;
int B6 = 19;

int D2 = 2;
int D3 = 3;
int D4 = 4;
int D5 = 5;
int D6 = 6;
int D7 = 7;

void setup() {
  
  pinMode(B1, INPUT);
  pinMode(B2, INPUT);
  pinMode(B3, INPUT);
  pinMode(B4, INPUT);
  pinMode(B5, INPUT);
  pinMode(B6, INPUT);

  pinMode(D2, OUTPUT);
  pinMode(D3, OUTPUT);
  pinMode(D4, OUTPUT);
  pinMode(D5, OUTPUT);
  pinMode(D6, OUTPUT);
  pinMode(D7, OUTPUT);
  
}

void loop() {
  
  if (digitalRead(BI) == HIGH && digitalRead(B2) == LOW) {
    
  digitalWrite(D2, HIGH);
  digitalWrite(D3, LOW);
}
  else{
  digitalWrite(D2, LOW);
  digitalWrite(D3, LOW);


if (digitalRead(B2) == HIGH && digitalRead(BI) == LOW) {
    
  digitalWrite(D3, HIGH);
  digitalWrite(D2, LOW);
}
  else{
  digitalWrite(D2, LOW);
  digitalWrite(D3, LOW);
}
}
}

I'm not an Arduino expert but it appears to that Bx is defined as the binary equivalent   forum.arduino.cc/.../480156 interesting 

You still have an issue with your B1 and BI.  BI is not being set as input, but B1 is.

So make sure you stick to the BI variable as B1 would just be a constant 1

it had on effect when i changed it