1
I have the following HTML structure:
<div class="col-xs-4">
    <div class="form-group">
        <label for="vencimentoBolsa">Vencimento:</label>
        <input type="text" class="form-control" name="dtVencimento" placeholder="Vencimento" required>
    </div>
    <div class="form-group">
        <label for="volumeBolsa">Volume:</label>
        <input type="text" class="form-control" name="volumeBolsa" placeholder="Volume" required>
    </div>
    <div class="form-group">
        <label for="unidadeVolume">Unidade Volume:</label>
        <select class="selectpicker" data-size="5" data-live-search="true" data-width="100%" name="unidadeVolume" required>
            <option selected disabled>Escolha uma opção</option>
            <option>Mililitro</option>
            <option>Litro</option>
        </select>
    </div>
</div>
The previous structure is as follows:

But I’d like it to stay the way it is:

I’ve tried to do it my way:
<div class="col-xs-4">
    <div class="form-group">
        <label for="vencimentoBolsa">Vencimento:</label>
        <input type="text" class="form-control" name="dtVencimento" placeholder="Vencimento" required>
    </div>
    <div class="col-xs-6">
        <div class="form-group">
            <label for="volumeBolsa">Volume:</label>
            <input type="text" class="form-control" name="volumeBolsa" placeholder="Volume" required>
        </div>
    </div>
    <div class="col-xs-6">
        <div class="form-group">
            <label for="unidadeVolume">Unidade Volume:</label>
            <select class="selectpicker" data-size="5" data-live-search="true" data-width="100%" name="unidadeVolume" required>
                <option selected disabled>Escolha uma opção</option>
                <option>Mililitro</option>
                <option>Litro</option>
            </select>
        </div>
    </div>
</div>
But there is a margin on the left and right of the inputs.
puts a specific id on the one you want to stay online, then changes its flotation requirements
– Walter Felipe