Formulário sem borda - #bootstrap
Componente recurso #floating #labels
Neste exemplo foram utilizados recursos #CSS auxiliares.
<!DOCTYPE html>
<html lang="pt-br" dir="ltr">
<head>
<meta charset="utf-8">
<title>Form bootstrap 5 -no border</title>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.9.1/font/bootstrap-icons.css">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3" crossorigin="anonymous">
<style media="screen">
.form-control,
.form-select {
border: 0;
}
.form-control:focus,
.form-select:focus {
-webkit-box-shadow: none;
box-shadow: none;
}
.bg-form {
background-color: #383434;
}
.bg-button-submit {
background-color: #282828;
}
</style>
</head>
<body>
<!-- created by @BrCodeSnippets -->
<div class="container mt-3 pt-3">
<div class="row">
<div class="col-12">
<div class="card p-3 bg-form">
<form class="row g-3">
<div class="col-12">
<h1 class="text-center fw-bolder text-white mt-3">Form bootstrap 5 - Floating labels</h1>
<hr>
</div>
<div class="col-12">
<div class="p-3 mb-3 text-white fw-bolder fs-3 border-5 border-start">
Cadastre-se
</div>
</div>
<div class="col-12">
<div class="form-floating">
<input type="text" autocomplete="off" class="form-control bg-light " id="inputName" placeholder="Name">
<label for="inputName">Name</label>
</div>
</div>
<div class="col-12 col-md-6">
<div class="form-floating">
<input type="email" class="form-control bg-light " id="inputEmail4" placeholder="Informe seu e-mail">
<label for="inputEmail4">Email address</label>
</div>
</div>
<div class="col-md-6">
<div class="form-floating">
<input type="password" class="form-control bg-light border-0 " id="inputPassword4" placeholder="Informe uma senha segura">
<label for="inputPassword4" class="form-label">Password</label>
</div>
</div>
<div class="col-12">
<div class="form-floating">
<input type="text" class="form-control bg-light " id="inputAddress" placeholder="1234 Main St">
<label for="inputAddress" class="form-label">Address</label>
</div>
</div>
<div class="col-md-6">
<div class="form-floating">
<input type="text" class="form-control bg-light " id="inputCity" placeholder="Cidade">
<label for="inputCity" class="form-label">City</label>
</div>
</div>
<div class="col-md-4">
<div class="form-floating">
<select id="inputState" class="form-select bg-light">
<option selected>Choose...</option>
<option>...</option>
</select>
<label for="inputState" class="form-label">State</label>
</div>
</div>
<div class="col-md-2">
<div class="form-floating">
<input type="text" class="form-control bg-light" id="inputZip" placeholder="Cep">
<label for="inputZip" class="form-label">CEP</label>
</div>
</div>
<div class="col-12">
<div class="form-floating">
<textarea class="form-control" placeholder="Leave a comment here" id="floatingTextarea" style="height:100px"></textarea>
<label for="floatingTextarea">Comments</label>
</div>
</div>
<div class="col-12">
<div class="form-check">
<input class="form-check-input" type="checkbox" id="gridCheck">
<label class="form-check-label shadow-sm text-white" for="gridCheck">
Concordo com os termos.
</label>
</div>
</div>
<div class="col-12 text-end">
<button type="submit" class="btn bg-button-submit w-100 bg-gradient p-3 text-center mb-2 text-white fw-bolder fs-3">Salvar</button>
<a href="#" class="text-primary shadow-sm">Precisa de ajuda? Clique aqui</a>
</div>
</form>
</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js" integrity="sha384-ka7Sk0Gln4gmtz2MlQnikT1wXgYsOg+OMhuP+IlRH9sENBO0LRn5q+8nbTov4+1p" crossorigin="anonymous"></script>
</body>
</html>