How can I access my sqlite3 database through the html template using Django?

Yes, if you have a model that will store the data from the fields you defined in your template then you can create a form that will store the data about that models fields, then you can just pass the form to the template, for example:

models.py

class Person(models.Model):
    name = models.CharField(max_length=20)
    age = models.IntegerField(default=1)

forms.py

from django import forms
from .models import Person

class PersonForm(forms.ModelForm)
    class Meta:
        model = Person
        fields = '__all__' # or pass an iterable with your model field names as strings

views.py

from .models import Person
from .forms import PersonForm

def create_person(request):
    if request.method == 'POST':
        form = PersonForm(request.POST)
        if form.is_valid():
            person = form.save() # creates and saves a new Person instance
            return redirect('person', pk=person.pk) # redirect to the view that displays the person
    else:
        form = PersonForm()
    return render(request, 'create_person.html', {'form': form}) # pass the form to the view in a context dictionary

def person(request, pk): # pass the primary key of a person to the view
    person = Person.objects.get(pk=pk)
    return render(request, 'person.html', {'person': person})

create_person.html ( this is the view that will have the form )

<form method="post">
    {% csrf_token %}
    {{ form.as_p }} <!-- render form fields inside <p> tags ( you can also use table or list ) -->
    <button type="submit" value="Save"></button>
</form>

person.html

<p>This is the page that belongs to the {{ person.name }}</p>
<p>The {{ person.name }} is {{ person.age }} years old.</p>

And finally set up the urls.py for your views:

from django.urls import path
from . import views 

urlpatterns = [
    path('create_person', views.create_person, name="create_person"),
    path('person/<int:pk>/', views.person, name="person") # pass the pk argument into the url path here 
]